Look here to learn about common eye conditions that you may have heard of but don’t know much about.
Age related macular degeneration or ARMD is the most common cause of irreversible vision loss for
people over the age of 60.
Age Related Macular Degeneration (ARMD) is the most common cause of irreversible vision loss for people over the age of 60. It is estimated that 2.5 million people in developed countries will suffer visual loss from this disorder and that there are approximately 200,000 new cases diagnosed every year. Macular degeneration is most common in people over the age of 65, but there have been some cases affecting people as young as their 40s and 50s. Symptoms include blurry or fuzzy vision, a reduction in color vision, straight lines like telephone poles and sides of buildings appear wavy and a dark or empty area may appear in the center of vision.
WHAT IS THE MACULA?
The macula is the small portion of the retina located at the center of this light sensitive lining at the back of the eye. Light rays from objects that we are looking at come to a focus on the retina and are converted into electrical impulses that are then sent to the brain. The macula is responsible for sharp straight-ahead vision necessary for functions such as reading, driving a car and recognizing faces.
The effect of this disease can range from mild vision loss to central blindness. That is, blindness “straight ahead” but with normal peripheral vision from the non-macular part of the retina which is undamaged by the disease.
TWO TYPES OF MACULAR DEGENERATION
Ninety percent of ARMD is of the “atrophic” or “dry” variety. It is characterized by a thinning of the macular tissueand the development of small deposits on the retina called drusen. Dry ARMD develops slowly and usually causes mild visual loss. The main symptom is often a dimming of vision when reading.
The second form of ARMD is called “exudative” or “wet” because of the abnormal growth of new blood vessels under the macula where they leak and eventually create a large blind spot in the central vision. This form of the disease is of much greater threat to vision than the more common dry type.
WHAT CAUSES ARMD?
Unfortunately, the cause of this eye condition is not fully understood, but it is associated with the aging process. As we age, we become more susceptible to numerous degenerative processes like arthritis, heart conditions, cancer, cataracts and macular degeneration. These conditions may be caused by the body’s overproduction of free radicals.
During the metabolic process, oxygen atoms with an extra electron are released. These extra electrons are quite destructive and cause cellular damage, alter DNA, and are thought to be at least partially responsible for many of the degenerative diseases mentioned above. The production of these free radicals is normal during metabolism but the body produces its own “anti-oxidants” to neutralize them.
Some of the vitamins in the food we eat also have anti-oxidant properties. These are vitamins A, C, E and beta-carotene. Unfortunately, smoking, poor nutrition and other lifestyle factors result in the body producing toomany free radicals. For this reason, lifestyle factors may contribute to the risk of ARMD.
There is some evidence to suggest that ARMD has a genetic basis, as the condition tends to run in families. The exact nature of this familial tendency, however, has not been clarified. It has been suggested from twin studies that there is a defect in the genes responsible for the integrity and health of the retina.
Exposure to certain types of light may also play a role. Studies performed on fishermen in the Chesapeake Bay suggest that long-term exposure to ultraviolet light from the sun may increase the risk of ARMD and other eye conditions such as the development of cataracts
HOW IS ARMD TREATED?
Although researchers are spending a great deal of time investigating the cause and treatment of ARMD, there is no real cure available. The goal of current treatment efforts is to attempt to stabilize the condition. For the more severe wet form of the disease, doctors have tried laser photocoagulation. This treatment, however, is not without dangers and is only beneficial in the very early stages of the condition, which is why early detection is so important. This technique involves directing a beam of laser light at the abnormal blood vessels in order to destroy them and prevent their leaking. Provided that the blood vessels have not grown under the macula, this treatment can be helpful in arresting the progress of the disease. If the blood vessels are already under the macula, the laser may cause scarring and permanent vision loss.
A type of treatment called photodynamic therapy (PDT) shows promise. A drug, injected into the arm travels to the affected eye and is then exposed to a non-thermal red light. This light activates the drug to close and seal off the abnormal blood vessels. The entire treatment only takes about 30 minutes and requires no anesthetic.
The latest treatment includes anti-VEGF (vascular endothelial growth factor) drugs which block the trouble-causing VEGF, reducing the growth of abnormal blood vessels and slowing their leakage.
Several new treatments are under development and scientific evaluation as well. These procedures may preserve more sight overall, though they are not cures that restore vision to normal.
ARE VITAMINS AND NUTRITION USEFUL?
No treatment exists for the dry form but a combination of specific vitamins and minerals has been demonstrated to help slow the progression of the disease. Anti-oxidant vitamins may help to neutralize the free radicals that are associated with this degenerative process. Zinc, one of the most common trace minerals in our body, is highly concentrated in the retina and surrounding tissues and is a requirement for chemical reactions in the retina. Fat-soluble anti-oxidant vitamins like vitamin A and vitamin E are stored in the body and can increase to toxic levels if over used and zinc may interfere with other trace minerals like copper. Caution should therefore be exercised in the use of vitamins and minerals. Ask Dr. Velasco which vitamins are right for you. A low-fat diet, rich in dark green leafy vegetables, including spinach, some types of leaf lettuce and broccoli, can slow vision loss due to macular degeneration as well.
If your eyelid rims are red and irritated, if they burn and itch or if you’ve noticed an oily discharge or scaly skin around them, you may have an inflammatory problem called “blepharitis“.
Blepharitis is a common, long-term inflammation of the eyelids and eyelashes. It affects people of all ages. Symptoms include irritation, itching, and occasionally a red eye.This condition frequently occurs in people who have a tendency towards oily skin, dandruff, or dry eyes.
Less frequently does ulcerative blepharitis occur in which hard crusts form around the eyelashes that can bleed or ooze when removed. If not treated, loss of eyelashes, distortion of the front edge of the eyelids and chronic tearing could occur.
WHAT ARE CAUSES OF BLEPHARITIS?
Bacteria reside on the surface of everyone’s skin at the base of the eyelashes. The resulting irritation, sometimes associated with over-activity of the nearby oil glands, causes dandruff-like scales and particles to form along the lashes and eyelid margins. Sometimes the scaling or bacteria produce only minor irritation and itching, but in some they may cause redness, stinging, or burning. Some people may develop a sensitivity or allergic reaction to the scales and bacteria which surround them. This can lead to more serious complications, including an inflammation of the eye tissues, particularly the cornea. Poor cleaning of the eyelids allows bacteria to reside on the lids and lashes, which in turn can cause blepharitis as well.
WHAT ARE THE TREATMENTS?
Blepharitis is usually not serious and can be treated easily. In certain cases, it may not be cured, but it can be controlled with a few simple daily measures. If left untreated, it can be very uncomfortable, unattractive, and lead to more serious problems.
To treat blepharitis, daily lid hygiene is required, which can include lid scrubs, warm soaks, and other various measures. It is important to keep the lid edges and surrounding skin clean with these techniques. For more serious cases, ointments containing antibiotics and sulfonamides should be applied to the edges of the eyelids with a cotton ball. Steroid drop can also be prescribed by Dr. Velasco to calm the inflammation.
While over-the-counter treatments for blepharitis are available, it is advisable to consult with Dr. Velasco the first time you experience this condition. If you have had blepharitis before and had experience with its treatment, using the over-the-counter ointments may be adequate. But, whether you have had the condition before or not, if the blepharitis is infectious, you should call Dr. Velasco as soon as possible to reduce the risk of having the infection spread and cause more serious conditions.
Red, watery eyes, inflamed lids, blurred vision and a sandy or scratchy feeling in the eyes may indicate that
you have conjunctivitis. The infectious form of the disease is commonly known as “pink eye”.
Conjunctivitis is an inflammation or infection of the conjunctiva, a thin, transparent layer covering the surface ofthe inner eyelid and the front of the eye. It affects people of all ages.
WHAT CAUSES CONJUNCTIVITIS?
The three main types of conjunctivitis are infectious, allergic and chemical. The infectious form, commonly known as “pink eye,” is caused by a contagious virus or bacteria. Your body’s allergies to pollen, cosmetics, animals or fabrics often bring on allergic conjunctivitis. Irritants like air pollution, noxious fumes and chlorine in swimming pools may produce the chemical form.
It is important to prevent spreading conjunctivitis. If contagious, measures can be taken to prevent spreading conjunctivitis to others.
Keep your hands away from your eyes;
Thoroughly wash hands before and after applying eye medications;
Do not share towels, washcloths, cosmetics or eyedrops with others;
Seek treatment promptly.
Small children, who may forget these precautions, should be kept away from school, camp and the swimming pool until the condition is cured.
Certain forms of conjunctivitis can develop into a serious condition that may harm your vision. Therefore, it is important to have conjunctivitis diagnosed and treated quickly.
HOW IS INFECTIOUS CONJUNCTIVITS TREATED?
Infectious conjunctivitis, caused by bacteria, is usually treated with antibiotic eye drops and/or ointment. Other infectious forms, caused by viruses, can’t be treated with antibiotics and must be fought off by your body’s immune system. If caught early enough, Dr. Velasco can do an in-house treatment that can shorten the course of the virus. On occasions antibiotics may be prescribed to prevent secondary bacterial infections from developing.
HOW ARE THE ALLERGIC AND CHEMICAL FORMS OF CONJUNCTIVITIS TREATED?
The ideal treatment for both forms is to remove the cause of the allergy or irritation. For instance, avoid contact with any animal if it causes an allergic reaction. Wear swimming goggles if chlorinated water irritates your eyes. In cases where these measures won’t work, prescription and over-the-counter eye drops are available to help relieve the discomfort.
Corneal arcus is a deposit of lipids causing a white or grayish ring at the periphery of the cornea.
In scientific terms, corneal arcus is “a corneal disease in which there is a deposition of phospholipid and cholesterol in the corneal stroma and anterior sclera.” Also called arcus senilis (when occurring in the elderly), arcus juvenilis (when occurring in the young) or arcus senilis corneae, the disease is found mostly at birth or later in life, becoming quite frequent in those over 50. It is a white or gray opaque ring in the margin of the cornea (in medical terms, “peripheral corneal opacity”), also defined as a “hazy ring at the edge of the cornea where the iris meets the white of the eye but does not impair vision”. It results from cholesterol deposits in or hyalinosis of the corneal stroma and may be associated with ocular defects or with familial hyperlipidemia.
It can be a sign of disturbance in lipid metabolism, an indicator of conditions such as hypercholesteremia, hyperlipoproteinemia or hyperlipidemia. Unilateral arcus is a sign of carotid artery disease or ocular hypotony (abnormally low intraocular pressure often related to uveitis).
In short Arcus juvenilus or senilis is a deposit of lipids causing a white ring at the periphery of the cornea. It is generallybenign and age-related; however, when seen in younger patients, there may be an association with elevatedblood cholesterol. It is prudent to test cholesterol and lipid levels during the next medical examination.
If your eyes sting, itch or burn, you may be experiencing the common signs of “dry eye.” A feeling of something foreign within the eye or general discomfort may also signal dry eye.
WHAT IS DRY EYE?
Dry eye describes eyes that do not produce enough tears. The natural tears that your eyes produce are composed of three layers:
The outer oily layer, which prevents or slows evaporation of the tear film;
The middle watery layer; which moisturizes and nourishes the front surface of the eye;
The inner mucus layer, which helps maintain a stable tear film.
Dry eye may occur because the volume of tears produced is inadequate (we all produce fewer tears as we get older, and in some cases this can lead to dry eye symptoms). It may result because the composition of the tears has changed so that they are unstable and evaporate more quickly.
WHAT CAUSES DRY EYE?
Dry eye symptoms can result from the normal aging process. Exposure to environmental conditions, as well as medications, such as antihistamines, oral contraceptives or anti-depressants, can contribute to the symptoms of dry eye. Or, dry eye can result from chemical or thermal burns to the eye. Dry eye may also be symptomatic of general health problems or other diseases. For example, people with arthritis are more prone to dry eye.
WILL DRY EYES HARM MY EYES?
If untreated, it can. Excessive dry eye can damage tissue and possibly scar the cornea at the front of your eye, impairing vision. Dry eye can make contact lens wear more difficult since tears may be inadequate to keep the lenses wet and lubricated. This can lead to irritation and a greater chance of eye infection. Therefore, it is important to follow the recommended treatment plan.
HOW IS IT DIAGNOSED?
During the examination, you will be asked about your general health, use of medications, and work and home environments to determine factors, which may be contributing to dry eye symptoms. This information will helpdecide whether to perform specific dry eye tests. To test for dry eye, diagnostic instruments that allow a highly magnified view of your eyes or small strips of paper or thread and special dyes to assess the quantity and quality of the tears may also be used.
HOW IS IT TREATED?
Dry eye cannot be cured, but your eyes’ sensitivity can be lessened and measures taken so your eyes remain healthy. The most frequent method of treatment is the use of artificial tears or tear substitutes. For more severe dry eye, ointment can be used, especially at bedtime. In some cases, small plugs may be inserted in the corner of the eyelids to slow drainage and loss of tears.
To keep dry eye symptoms in check, you and Dr. Velasco need to work together. If you have increased dryness or redness that is not relieved by the prescribed treatment, let us know as soon as possible.
The scariest thing about glaucoma is that it can steal your vision gradually and without you noticing. The best defense against glaucoma is a regular eye examination. Glaucoma most often strikes people over age 50. But it is recommended that during adult life everyone be tested at least every two years.
Some people with glaucoma do experience symptoms, but symptoms vary depending on the type of glaucoma.
PRIMARY ANGLE GLAUCOMA
By far the most common type, primary open-angle glaucoma develops gradually and painlessly. Since there are no early warning signs, it can slowly destroy your vision without your knowing it. The first indication may only occur after some considerable vision loss.
ACUTE ANGLE CLOSURE GLAUCOMA
This results from a sudden blockage of the drainage channels within your eye, causes a rapid build-up of pressure inside your eye accompanied by blurred vision, the appearance of colored rings around lights and sometimes extreme pain or redness in the eyes.
WHAT IS GLAUCOMA?
The build-up of pressure inside your eye leads to glaucoma. Aqueous fluid, which fills the space at the front of the eye just behind the cornea, is made behind the iris (the colored part of the eye) in the ciliary body. It flows through the pupil (the dark hole in the center of the iris), and drains from the ‘anterior chamber angle,’ which is the junction between the edge of the iris and the cornea. If this outflow of liquid is impaired at all, there is a build-up of pressure inside the eye that damages the optic nerve, which carries visual images to the brain. The result is a loss of peripheral vision. Thus, while glaucoma sufferers may be able to read the smallest line on the vision test, they may find it difficult to move around without bumping into things or to see moving objects to the side.
WHAT CAUSES GLAUCOMA?
Some causes are known, others are not. Causes differ depending on the type of glaucoma. The exact cause of open-angle glaucoma, where the drainage channels for the aqueous appear to be open and clear, is not known. Closed-angle glaucoma can occur when the pupil dilates or gets bigger and bunches the iris up around its edge, blocking the drainage channel. An injury, infection or tumor in or around the eye can also cause internal eye pressure to rise either by blocking drainage or displacing tissues and liquid within the eye. A mature cataract also can push the iris forward to block the drainage ‘angle’ between the iris and the cornea. Glaucoma can occur secondarily to a number of other conditions, such as diabetes, or as a result of some medications for other conditions.
WHO GETS GLAUCOMA?
Glaucoma most frequently occurs after age 40, but can occur at any age. If you’re of African heritage, you are more likely to develop open-angle glaucoma — and at an earlier age — than if you’re Caucasian. Asians are more likely to develop narrow-angle glaucoma.
You have a higher risk of developing glaucoma if a close family member has it or if you have high blood pressure or high blood sugar (diabetes). There is also a greater tendency for glaucoma to develop in individuals who are nearsighted. Those at heightened risk for glaucoma should have their eyes checked at least once a year
WHY IS GLAUCOMA HARMFUL TO YOUR VISION?
The optic nerve, located at the back of the eye, carries visual information to the brain. As the fibers that make up the optic nerve are damaged by glaucoma, the amount and quality of information sent to the brain decreases and a loss of vision occurs.
WILL I GO BLIND FROM GLAUCOMA?
If diagnosed at an early stage, glaucoma can be controlled and little or no further vision loss should occur. If left untreated, side awareness (peripheral vision) and central vision will be destroyed and blindness may occur.
HOW IS GLAUCOMA DETECTED?
Tests for glaucoma are part of a comprehensive eye examination. A simple and painless procedure called tonometry measures the internal pressure of your eye. Ophthalmoscopy examines the back of the eye to observe the health of the optic nerve. A visual field test, a very sensitive test that checks for the development of abnormal blind spots, may also be completed.
HOW IS GLAUCOMA TREATED?
Glaucoma is usually treated with prescription eye drops and medicines. In some cases, surgery may be required to improve drainage. The goal of the treatment is to prevent loss of vision by lowering the pressure in the eye.
WILL MY VISION BE RESTORED AFTER TREATMENT?
Unfortunately, any vision loss as a result of glaucoma is permanent and cannot be restored. This is why regular eye examinations are important.
Glaucoma cannot be prevented, but early detection and treatment can control glaucoma and reduce the chances of damage to the eye and a loss of sight.
WHAT IS HERPES SIMPLEX?
Herpes Simplex is a virus that infects the skin, mucous membranes and nerves. There are two major types of herpes simplex virus (HSV). Type I is the most common and is responsible for herpes simplex eye disease and the familiar “cold sore” or “fever blister.” Type II is responsible for sexually transmitted herpes and rarely causes infection above the waist.
An original infection with herpes simplex type I occurs in 90% of the population, usually during childhood or adolescence. The infection, sometimes only a mild sore mouth or throat, comes from close personal contact with an infected person and usually passes without notice.
After the original infection, the virus goes into a quiet or dormant period, living in nerve cells that supply the skin or eye. Occasionally, the virus reactivates and causes a recurrent “cold sore” or “fever blister.”
WHAT IS HERPES SIMPLEX EYE DISEASE?
The most common herpes simplex eye disease caused by HSV type I is a recurrent eye infection of the cornea, the clear front window of the eye, which can potentially threaten sight. The infection varies in duration, severity and response of treatment, depending in part on which of several different strains of HSV type I caused the original infection. It can be considered a “cold sore” or “fever blister” of the eye.
The disease usually begins on the surface of the cornea. The eye turns red, is uncomfortable and sensitive to light. For most people, this will be the only episode. Unfortunately, one out of four people who have a corneal infection are likely to have a recurrence within two years.
The process may go deeper into the cornea and cause permanent scarring or inflammation inside the eye. Chronic ulcers, which are sometimes very difficult to heal, may also develop on the cornea.
Herpes simplex eye disease usually occurs in only one eye and rarely spreads to the other eye. Spreading the infection to another person is unlikely. In people with poor immunity, the herpes simplex virus may infect other parts of the eye or body, such as the retina or brain, but this occurs infrequently.
It is important to remember that herpes simplex eye disease is not usually caused by HSV type II, the sexually transmitted herpes. While possible, sexual transmission of herpes eye disease is extremely rare.
HOW IS HERPES SIMPLEX OF THE EYE TREATED?
Treatment depends on the extent of the disease. Antiviral medications are commonly used and may need to be applied as frequently as one drop per hour. At times it may be necessary to scrape the surface of the cornea, to patch the eye, or to use a variety of medications. In cases of severe scarring and vision loss, a corneal transplant may be required.
It is very important to consult with Dr. Velasco before beginning any treatment since some medications may actually make the disease worse.
Keratoconus is an uncommon condition in which the cornea, the clear front window of the eye, becomes thin and protrudes. This abnormal shape can cause serious distortion of vision. Its progression is generally slow and can stop at any stage from mild to severe.
WHAT CAUSES KERATOCONUS?
Research indicates that keratoconus may be caused by an excess of enzymes that break down the proteins within the corneal surface, causing the cornea to thin and protrude. The genetic inheritance of keratoconus has not clearly been determined. It appears that it may involve a number of different genes. Blood relatives of someone affected with keratoconus may have minor changes in their corneas that indicate that keratoconus probably varies both in the specific genetic cause, as well as in its expression within a family. Hereditary influences suggest that approximately 13% of patients have other family members with keratoconus. Unless there is evidence of keratoconus in successive generations of the family, there is only about a 1 in 10 chance that the children will develop keratoconus.
Vigorous eye rubbing can contribute to the disease process. People with keratoconus should avoid rubbing their eyes. This is sometimes very difficult because some allergies, which cause itchy, irritated eyes, are more commonly associated in patients with keratoconus.
WHO GETS KERATOCONUS?
The actual prevalence of Keratoconus is not known. While it is not one of the most common of eye diseases, it is by no means rare. It has been estimated to occur in 1 out of every 2,000 persons in the general population. The disease usually shows up in young people at puberty or in their late teen years, but has also been first diagnosed in individuals in their forties and fifties as well. It is found in all parts of the US, and the rest of the world, with no significant geographic, gender, ethnic, or social pattern.
WHAT ARE SYMPTOMS OF KERATOCONUS?
Blurring and distortion of vision are the earliest symptoms of keratoconus. Symptoms usually appear in the late teens or early twenties. The disease will often progress slowly for 10 to 20 years, then stop. In the early stages, vision may be only slightly affected, causing glare, light sensitivity and irritation. Each eye may be affected differently. As the disease progresses and the cornea steepens and scars, vision may become distorted. A sudden decrease in vision can occur if the cornea swells. This is called acute hydrops. The cornea swells when the elastic part of the cornea develops a tiny crack, created by the strain of the cornea’s protruded cone-like shape. The swelling may persist for weeks or months as the crack heals and is gradually replaced by scar tissue.
HOW IS KERATOCONUS TREATED?
In the early stages of keratoconus, eyeglasses may be all that is needed to correct the mild prescription induced by the condition. However, as the keratoconus progresses, the corneal surface becomes more irregular making the vision through eyeglasses less acceptable. If eyeglasses cannot fully correct vision, rigid contact lenses can make a remarkable difference in the clarity of vision. Contact lenses work by creating a new artificial, smooth surface to the front of the eye, thereby correcting the induced prescription. Newer materials and designs enable many people with keratoconus to enjoy wearing contact lenses longer. Approximately 90% of individuals with keratoconus successfully manage their condition with contact lenses.
When contact lenses cannot improve your vision adequately, a corneal transplant may be necessary. It is estimated that only 20% of people with keratoconus will require corneal transplant surgery. Keratoconus is one of the most common reasons for corneal transplant, and one of the most successful. Although this is a very successful procedure, it also carries some serious complications that can occur. Because of this, corneal transplants are usually considered only in those cases in which contact lenses cannot be worn or do not provide adequate vision. Dr. Velasco can discuss the risks, benefits, and alternatives to surgery in your particular case.
Other ocular conditions are often seen in association with keratoconus, such as eyelid inflammation (blepharitis) or atopic or allergic red eye (conjunctivitis). These conditions can be treated with the appropriate drops and cleansing routine to enable comfortable contact lens wear. Dr. Velasco can advise you on how to appropriately treat these conditions.
Retinal detachment is a disorder of the eye in which the retina peels away from its underlying layer of support tissue. Initial detachment may be localized, but without rapid treatment the entire retina may detach, leading to vision loss andblindness. It is a medical emergency.
The retina is a thin layer of light-sensitive tissue on the back wall of the eye. The optical system of the eye focuses light on the retina much like light is focused on the film in a camera. The retina translates that focused image into neural impulses and sends them to the brain via the optic nerve. Occasionally, posterior vitreous detachment, injury or trauma to the eye or head may cause a small tear in the retina. The tear allows vitreous fluid to seep through it under the retina, and peel it away like a bubble in wallpaper.
Rhegmatogenous retinal detachment – A rhegmatogenous retinal detachment occurs due to a hole, tear, or break in the retina that allows fluid to pass from the vitreous space into the subretinal space between the sensory retina and the retinal pigment epithelium.
Exudative, serous, or secondary retinal detachment – An exudative retinal detachment occurs due to inflammation, injury or vascular abnormalities that results in fluid accumulating underneath the retina without the presence of a hole, tear, or break.
Tractional retinal detachment – A tractional retinal detachment occurs when fibrovascular tissue, caused by an injury, inflammation or neovascularization, pulls the sensory retina from the retinal pigment epithelium.
A substantial number of retinal detachments result from trauma, including blunt blows to the orbit, penetrating trauma, and concussions to the head. A retrospective Indian study of 500 cases of rhegmatogenous detachments found that 11% were due to trauma, and that gradual onset was the norm, with over 50% presenting more than one month after the inciting injury.
The risk of retinal detachment in otherwise normal eyes is around 5 in 100,000 per year. Detachment is more frequent in the middle-aged or elderly population with rates of around 20 in 100,000 per year. The lifetime risk in normal eyes is about 1 in 300.
Retinal detachment is more common in those with severe myopia (above 5-6 diopters), as their eyes are longer and the retina is stretched thin. The lifetime risk increases to 1 in 20. Myopia is associated with 67% of retinal detachment cases. Patients suffering from a detachment related to myopia tend to be younger than non-myopic detachment patients. Retinal detachment can occur more frequently after surgery for cataracts. The estimate of risk of retinal detachment after cataract surgery is 5 to 16 per 1000 cataract operations. The risk may be much higher in those who are highly myopic, with a frequency of 7% reported in one study. Young age at cataract removal further increased risk in this study. Long term risk of retinal detachment after extracapsular and phacoemulsification cataract surgery at 2, 5 and 10 years was estimated in one study to be 0.36%, 0.77% and 1.29%, respectively.
Tractional retinal detachments can also occur in patients with proliferative diabetic retinopathy or those with proliferative retinopathy of sickle cell disease. In proliferative retinopathy, abnormal blood vessels (neovascularization) grow within the retina and extend into the vitreous. In advanced disease, the vessels can pull the retina away from the back wall of the eye causing a traction retinal detachment.
Although retinal detachment usually occurs in one eye, there is a 15% chance of developing it in the other eye, and this risk increases to 25-30% in patients who have had cataracts extracted from both eyes.
A retinal detachment is commonly preceded by a posterior vitreous detachment which gives rise to these symptoms:
flashes of light (photopsia) – very brief in the extreme peripheral (outside of center) part of vision
a sudden dramatic increase in the number of floaters
a ring of floaters or hairs just to the temporal side of the central vision
a slight feeling of heaviness in the eye
Although most posterior vitreous detachments do not progress to retinal detachments, those that do produce the following symptoms:
– A dense shadow that starts in the peripheral vision and slowly progresses towards the central vision
– The impression that a veil or curtain was drawn over the field of vision,
– Straight lines (scale, edge of the wall, road, etc.) that suddenly appear curved (positive Amsler grid test),
– Central visual loss.
There are several methods of treating a detached retina which all depend on finding and closing the holes (tears) which have formed in the retina.
In this treatment, Adatomed Silicon Oil is a sterile, colorless liquid injected into the eye and mechanically holds the retina in place until it reattaches. The oil is not intended to remain in the eye permanently, but is usually removed within a year. This treatment has shown to be particularly effective in retinal detachment related to Cytomegalovirus secondary to AIDS.
CRYOPEXY AND LASER PHOTOCOAGULATION
Cryotherapy (freezing) and laser photocoagulation are treatments used to create a scar/adhesion around the retinal hole to prevent fluid from entering the hole and accumulating behind the retina and exacerbating the retinal detachment. Cryopexy and photocoagulation are generally interchangeable. However, cryopexy is generally used in instances where there is a lot of fluid behind the hole; laser retinopexy will not take.
SCLERAL BUCKLE SURGERY
Scleral buckle surgery is an established treatment in which the eye surgeon sews one or more silicone bands (or “tyres”) to the outside of the eyeball. The bands push the wall of the eye inward against the retinal hole, closing the hole and allowing the retina to re-attach. The bands do not usually have to be removed. The most common side effect of a scleral operation is myopic shift. That is, the operated eye will be more short sighted after the operation.
This operation is generally performed in the doctor’s office under local anesthesia. It is another method of repairing a retinal detachment in which a gas bubble is injected into the eye after which laser or freezing treatment is applied to the retinal hole. The patient’s head is then positioned so that the bubble rests against the retinal hole. Patients may have to keep their heads tilted for several days to keep the gas bubble in contact with the retinal hole. The surface tension of the air/water interface seals the hole in the retina, and allows the retinal pigment epithelium to pump the subretinal space dry and pull the retina back into place. This strict positioning requirement makes the treatment of the retinal holes and detachments that occurs in the lower part of the eyeball impractical. This procedure is usually combined with cryopexy or laser photocoagulation.
Vitrectomy is an increasingly used treatment for retinal detachment in countries with modern healthcare systems. It involves the removal of the vitreous gel and is usually combined with filling the eye with a gas bubble. Advantages of this operation is that there is no myopic shift after the operation. A disadvantage is that a vitrectomy always leads to more rapid progression of a cataract in the operated eye. In many places vitrectomy is the most commonly performed operation for the treatment of retinal detachment.
Retinal detachment can sometimes be prevented. The most effective means is by educating people to seek ophthalmic medical attention if they suffer symptoms suggestive of a posterior vitreous detachment. Early examination allows detection of retinal tears which can be treated with laser or cryotherapy. This reduces the risk of retinal detachment in those who have tears from around 1:3 to 1:20.
There are some known risk factors for retinal detachment. There are also many activities which at one time or another have been forbidden to those at risk of retinal detachment, with varying degrees of evidence supporting the restrictions.
Cataract surgery is a major cause, and can result in detachment even a long time after the operation. The risk is increased if there are complications during cataract surgery, but remains even in apparently uncomplicated surgery. The increasing rates of cataract surgery, and decreasing age at cataract surgery, inevitably lead to an increased incidence of retinal detachment.
Trauma is a less frequent cause. Activities which can cause direct trauma to the eye (boxing, kickboxing, karate, etc.) may cause a particular type of retinal tear called a retinal dialysis. This type of tear can be detected and treated before it develops into a retinal detachment. For this reason governing bodies in some of these sports require regular ophthalmic examination.
Individuals prone to retinal detachment due to a high level of myopia are encouraged to avoid activities where there is a risk of shock to the head or eyes, although without direct trauma to the eye the evidence base for this may be unconvincing.
Some doctors recommend avoiding activities that increase pressure in the eye, including diving, skydiving, again with little supporting evidence. According to one medical website, retinal detachment does not happen as a result of straining your eyes, bending or, heavy lifting. Therefore, heavy weightlifting would appear to be fine. However, two scientific articles have noted cases of retinal detachment or maculopathy due to weightlifting (specifically with the Valsalva method), and a third documented an increase in blood pressure in the eye during weightlifting.
Activities that involve sudden acceleration or deceleration also increase eye pressure and are discouraged. These include bungee jumping and drag racing, and may also include rollercoaster rides.
A small area of redness and pain on the margin of your eyelid may indicate that you have a stye, known in medical terms as an external hordeolum. A stye is a blocked gland at the edge of the lid that has become infected by bacteria, usually Staphylococcus aureus.
The area of redness and pain will eventually form a ‘point’. Until this occurs, warm compresses should be applied to the area for 15 minutes three-to-four times a day. The compresses should be followed by the application of sulphonamide or antibiotic ointment to the stye, available by prescription. Check with your eye care practitioner.
Once the stye has ‘pointed’, it can usually be expressed (squeezed gently to empty its contents), after which the lids should be cleaned. Treatment with the ointment and or oral antibiotics should be continued until symptoms have cleared.
Sometimes it is necessary for the stye to be lanced to assist with expression.
WHAT IS UVEITIS?
Uveitis is an inflammation of the middle layer of the eye called the uvea. This includes the iris, the ciliary body and the choroid. Uveitis can occur in one or both eyes. Inflammation of the uvea may involve other parts of the eye, or any part of the eye, including the cornea, the sclera, the vitreous body, the retina and the optic nerve.
WHAT ARE TYPES OF UVEITIS?
When Dr. Velasco diagnoses and treats uveitis, he may categorize it in different ways. Uveitis is often grouped by the part of the uvea it affects.
Anterior uveitis affects the front of the eye. It is often called iritis, because it mainly affects the area around the eye’s iris. Anterior uveitis is the most common type of uveitis in children and adults making up 40- 70% of all uveitis. It is usually acute (i.e. comes on suddenly and lasts for less than 6 weeks) and is associated with pain, light sensitivity, blurred vision and redness. Although it can be caused by a number of different kinds of arthritis and inflammatory diseases of the body, in most cases, the cause is unknown.
Intermediate Uveitis is an inflammation of the ciliary body, the front end of the retina, and the vitreous. The vitreous body is a clear gel-like substance that fills the inside of the eyeball between the lens and the retina. Intermediate uveitis is the least common type of uveitis, making up only 7-15% of cases. It is also known as cyclitis, pars planitis or vitritis.
Symptoms include floaters and blurry vision. People with intermediate uveitis are more likely to have chronic inflammation. Chronic uveitis is defined as uveitis lasting longer than 6 weeks. In most cases, the cause is unknown. An inflammatory disease called sarcoidosis, MS (multiple sclerosis, an inflammatory disease that affects thebrain and spinal cord) or Lyme disease may cause some cases of intermediate uveitis.
Posterior uveitis is an inflammation of the choroid, retina and optic nerve. The optic nerve is the path that carries images from the retina to the brain. It can be seen in 15-22% of uveitis types. Generally it is chronic (long standing- can last weeks to months to yeasrs), recurrent (in which a patient has multiple flare-ups between periods of a quiet eye) and affects both eyes. The underlying cause is often a result of an immune disease. Infections caused by the organism toxoplasmosis are the most ccommon cause of posterior uveitis.
In some cases, inflammation can affect the entire uvea. This inflammation is sometimes called panuveitis. People with panuveitis may be more likely to experience vision loss from the condition.
Symptoms include floaters, blurriness or loss of vision. As with other kinds of uveitis, the cause of panuveitis is often unknown.
IS THE DISEASE SERIOUS?
If untreated, anterior uveitis can lead to other eye problems and cause permanent damage. It usually responds well to treatment, however there may be a tendency for the condition to recur.
HOW IS UVUEITIS DIAGNOSED?
Since the symptoms of anterior uveitis are similar to those of some other eye diseases, Dr. Velasco will carefully examine the inside of the eye, under bright light and high magnification, to determine the presence and severity of the condition. Dr. Velasco may also perform other diagnostic procedures and arrange for otehr tests to help pinpoint the cause.
WHAT IS THE TREATMENT OF UVEITIS?
Prescription eyedrops that dilate the pupils in combination with anti-inflammatory drugs are usually needed. Treatment may take several days, or up to a few weeks in some cases. The condition must be monitored closely by Dr. Velasco who will regulate your medication. Vision loss from uveitis can usually be prevented if diagnosed and treated. It is very important for Dr. Velasco to try and determine the underlying cause of the inflammation. Treatment for the underlying cause will help prevent future occurences of the episodes.
While a comprehensive eye examination can determine for certain if you have a cataract forming, there are anumber of signs and symptoms that may indicate a cataract. Among them are:
Gradual blurring or hazy vision where colors may seem yellowed;
The appearance of dark spots or shadows that seem to move when the eye moves;
A tendency to become more nearsighted because of increasing density of the lens;
Double vision in one eye only;
A gradual loss of color vision;
A stage where it is easier to see without glasses;
The feeling of having a film over the eyes; and
An increased sensitivity to glare, especially at night.
WHAT IS A CATARACT?
A cataract is a clouding of the normally clear crystalline lens of the eye. This prevents the lens from properly focusing light on the retina at the back of the eye, resulting in a loss of vision. A cataract is not a film that grows over the surface of the eye, as is often commonly thought.
WHY ARE THEY CALLED CATARACTS?
Sometimes cataracts can be seen as a milkiness on the normally black pupil. In ancient times, it was believed this cloudiness was caused by a waterfall – or cataract – behind the eye.
WHO GETS CATARACTS?
Cataracts are most often found in persons over the age of 55, but they are also occasionally found in younger people, including newborns.
WHAT CAUSES CATARACTS?
It is known that a chemical change within the eye causes the lens to become cloudy. The change may be due to advancing age or it may be the result of heredity, an injury or a disease. Excessive exposure to ultraviolet or infrared radiation present in sunlight or from furnaces, cigarette smoking and/or the use of certain medications are also cataract risk factors. Cataracts usually develop in both eyes, often at different rates.
CAN CATARACTS BE PREVENTED AND TREATED?
Currently, there is no proven method to prevent cataracts from forming. If your cataract develops to a point that daily activities are affected, you will be referred to an eye surgeon who may recommend the surgical removal of the cataract. Prescription changes in your eyewear will help you see more clearly until surgery is necessary, but surgery is the only proven means of effectively treating cataracts. The surgery is relatively uncomplicated and has a very high success rate.
WHEN WILL I NEED CATARACTS REMOVED?
Cataracts may develop slowly over many years or they may form rapidly in a matter of months. Some cataracts never progress to the point that they need to be removed. Usually, you will be ready to have the cataract removed when it is having a significant adverse effect on your lifestyle. Our office will arrange a consultation with a surgeon who will decide on the appropriate time for removal. Most people wait until the cataracts interfere with daily activities before having them removed.
WHAT HAPPENS AFTER CATARACT SURGERY?
You, along with your doctors, will decide on the type of post-cataract vision correction that you will use. Intraocular lens implants, inserted in your eye at the time of surgery, serve as a “new lens” and are the most frequent form of visual correction. In some cases, however, eyeglasses or contact lenses may also be needed to provide the most effective post-cataract vision. Cataract surgery has now developed to the point where most procedures are completed in a day and overnight stays in hospital are unnecessary. The results are usually excellent and patients are often able to appreciate a significant improvement in vision almost immediately following surgery.
Diabetes, a disease that prevents your body from making or using insulin to break down sugar in your bloodstream. When not controlled it can affect your eyes and your vision. Fluctuating or blurring of vision, intermittent double vision, loss of peripheral vision and flashes and floaters within the eyes may be symptoms related to diabetes. Sometimes the early signs of diabetes are detected during a thorough eye examination. Diabetes can cause changes in nearsightedness and farsightedness and lead to premature presbyopia (theinability to focus on close objects). It can result in cataracts, glaucoma, a lack of eye muscle coordination (strabismus) and decreased corneal sensitivity. The most serious eye problem associated with diabetes is diabetic retinopathy, which, if not controlled, can lead to blindness.
WHAT IS RETINOPATHY?
Diabetic retinopathy occurs when there is a weakening or swelling of the tiny blood vessels in the retina of your eye, resulting in blood leakage, the growth of new blood vessels and other changes
CAN VISION LOSS FROM DIABETES BE PREVENTED?
Yes, in a routine eye examination, your eye care practitioner can diagnose potential vision-threatening changes in your eyes that may be treated to prevent blindness. However, once damage has occurred, the effects are usually permanent. It is important to control your diabetes as much as possible to minimize the risk of developing retinopathy.
HOW IS DIABETIC RETINOPATHY TREATED?
In the early stages, diabetic retinopathy can be treated with laser therapy. A bright beam of light is focused on the retina, causing a burn that seals off leaking blood vessels. In other cases, surgery inside the eye may be necessary. Early detection of diabetic retinopathy is crucial. It is routinely screened for in an eye examination.
ARE THERE RISK FACTORS FOR DEVELOPING DIABETES?
Several factors that increase the risk of developing retinopathy include smoking, high blood pressure, excessive alcohol intake and pregnancy.
HOW CAN DIABETES RELATED EYE PROBLEMS BE PREVENTED?
Diabetes-related eye problems can be prevented by monitoring and maintaining control of your diabetes. See your physician regularly and follow instructions about diet, exercise and medication. A thorough dilated eye examination when first diagnosed as a diabetic, at least annually thereafter, is recommended.
Hypertension, most commonly referred to as “high blood pressure”, HTN or HPN, is a medical condition in which the blood pressure is chronically elevated.
HOW CAN HTN AFFECT THE EYES?
Hypertension or high blood pressure leads to many changes in the blood vessels of the body. These same changes in blood vessels affect the eyes in many ways. They can cause the following problems:
Branch retinal vein occlusion (BRVO) and vitreous hemorrhage
Optic nerve involvement (Optic neuropathy)
Involvement of the nerves supplying the eye muscles, leading to temporary paralysis or weakness of these muscles
WHAT ARE THE SYMPTOMS?
Many of these conditions may not have any symptoms in the initial stages. Therefore, it is important to have a periodic eye exam to detect them.
Branch retinal vein occlusion (BRVO) may lead to a blurring of vision especially for fine work. A vitreous hemorrhage may lead to a more severe loss of vision associated with a shower of red floaters.
Optic neuropathy may also lead to a loss of vision, which is painless and not associated with any floaters.
Paralysis or weakness of the muscles of the eye leads to restriction of movement of the eye and double vision.
WHAT IS THE ROLE OF LASER TREATMENT IN HTN?
BRVO is commonly associated with high blood pressure and changes of hypertensive retinopathy. This
condition may lead to loss of vision by two mechanisms:
Macular edema (swelling of the region of macula): The macula is the central region of the retina and is important for seeing fine details. A swelling in this region leads to a decrease in vision. This condition can be treated with laser therapy.
Vitreous hemorrhage: Sometimes BRVO may lead to formation of new vessels in the retina. These vessels are abnormal and very fragile. They may bleed, causing vitreous hemorrhage and loss of vision. With timely detection, these new vessels can be eliminated via laser therapy.
Macroaneurysm: This is an uncommon manifestation of hypertension. Untreated, this may cause bleeding intvitreous and thus loss of vision. This condition can be treated with laser therapy.
WHY IS AN EYE CHECK UP IMPORTANT WITH HTN?
The eye is the only organ of the body where one can observe the blood vessels directly. By examining your eyes, Dr. Velasco may observe the changes in blood vessels caused by hypertension. This also provides information about the severity of the disease elsewhere in the body.
Moreover, presence of swelling of the disc (grade 4 hypertensive retinopathy) is an indicator of a very severe, life threatening rise in blood pressure, which warrants emergency treatment.
Farsightedness or long-sightedness is often referred to by its medical names, hypermetropia or hyperopia. This is a vision condition in which distant objects are usually seen clearly, but close ones are difficult to bring into proper focus.
Hyperopia causes the eyes to exert extra effort to see close up. After viewing near objects for an extended period, you may experience blurred vision, headaches and eyestrain. Children who are farsighted may find reading difficult. Hyperopia is not a disease, nor does it mean that you have “bad eyes.” It simply means that you have a variation in the shape of your eyeball. Many people have some degree of farsightedness, yet it is only a problem if it significantly affects the ability to see well. The degree of variation will determine whether or not you will need corrective lenses.
WHAT IS FARSIGHTEDNESS?
Hyperopia most commonly occurs because the eyeball is too short; that is, shorter from front to back than is normal. In some cases, hyperopia may be caused by the cornea having too little curvature. Exactly why eyeball shape varies is not known, but the tendency for farsightedness is inherited. Environmental factors may be involved too, but to a lesser degree than heredity. Our ability to “see” starts when light enters the eye through the cornea. The shape of the cornea, lens and eyeball help bend (refract) light rays in such a manner that light is focused into a point precisely on the retina.
If, as in farsightedness, the eyeball is too short, the “point of light” focuses on a location behind the retina, instead of on the correct area of the retina, known as the fovea. As a result, at the point on the retina where a fine point of light should be focused, there is a disk-shaped area of light. Since light is not focused when it hits the retina, vision is blurred. Convex lenses are prescribed to bend light rays more sharply and bring them to focus on the retina.
HOW COMMON IS FARSIGHTEDNESS?
Farsighted people are the majority. The condition only presents a problem if it creates blurred vision, causes headaches or results in reading difficulties. It is estimated that over half the people who wear eyeglasses are wearing them because of a focusing problem due to farsightedness or presbyopia, a natural decrease in focusing ability at near distance.
HOW IS IT DIAGNOSED AND TREATED?
Hyperopia is seldom diagnosed in school eye-screening tests, which typically test only the ability to see objects at a distance. A comprehensive eye examination by Dr. Velasco that checks both near and far vision is necessary to diagnose farsightedness. In some cases it may be necessary for Dr. Velasco to use drops during the examination to relax the eye muscles and ensure that the full degree of hyperopia is detected. This test, called a cycloplegic examination, is necessary because the muscles which focus the eye are so accustomed to being used to compensate for the hyperopia that the muscles go into “spasm” and cannot relax without being forced to do so.
Corrective convex lenses (positive powers) in glasses or contact lenses are usually prescribed. They bend light rays more sharply and bring them to focus on the retina. If you do not have other vision problems such as astigmatism, you may only need glasses for reading or other tasks performed at a close range. In some instances, refractive surgeries such as LASIK can be performed.
To determine the best avenue of treatment, questions about your lifestyle, occupation, daily activities and general health status may be asked by Dr. Velasco and the staff at iFocus Vision Center. For instance, you may be asked whether or not you frequently need near vision. Providing candid, considered answers to the questions will help assure that your corrective lenses contribute to clear sight and general comfort.
A comprehensive eye examination by Dr.Velasco at the recommended intervals will ensure that minor changes in vision are diagnosed and treated so that your vision will remain as clear and comfortable as possible.
a vision condition in which distant objects are usually seen clearly, but close ones are difficult to bring into
proper focus. Hyperopia causes the eyes to exert extra effort to see close up. After
Nearsightedness, or myopia, as it is medically termed, is a vision condition in which near objects are generally
seen clearly, but distant objects are blurred and do not come into focus. Myopia is a term that comes from a Greek word meaning “closed eyes.” Myopia is not a disease, nor does it mean that you have “bad eyes.” It simply refers to a variation in the shape of your eyeball. The degree of variation determines whether or not you will need corrective eyewear.
WHAT IS NEARSIGHTEDNESS?
Myopia most often occurs because the eyeball is too long, rather than the normal, more rounded shape. Another less frequent cause of myopia is that the cornea, the eye’s clear outer window, is too curved. There is some evidence that nearsightedness may also be caused by too much close vision work. Our ability to “see” starts when light enters the eye through the cornea. The shape of the cornea, lens and eyeball help bend (refract) light rays in such a manner that light is focused into a point precisely on the retina.
In contrast, if you are nearsighted, the light rays from a distant point are focused at a place in front of the retina. As the light will only be focused in that one place, by the time it reaches the retina it will have “defocused” again, forming a blurred image. Myopia usually occurs between the ages of 8 to 12 years. Since the eyes continue to grow during childhood, nearsightedness almost always occurs before the age of 20. Often the degree of myopia increases as the body grows rapidly, then levels off in adulthood. During the years of rapid growth, frequent changes in prescription eyewear may be needed to maintain clear vision. It is important to bear in mind that the frequent changes in prescription are not making the eyes “weaker”. During the growth period that occurs during the teen years, the eye is also growing rapidly and hence the degree of blur is also increasing. As the growth cycle slows the prescription changes slow correspondingly.
HOW COMMON IS MYOPIA?
Nearsightedness is a very common vision condition that affects nearly 30 percent of the American population.
HOW IS MYOPIA DIAGNOSED AND TREATED?
Myopia is often suspected when a teacher notices a child squinting to see a blackboard or a child performs poorly during a routine eye screening. Further examination by Dr. Velasco will reveal the degree of the problem. A comprehensive eye examination by Dr. Velasco will detect myopia. Yearly examinations should follow after myopia has been discovered to determine whether the condition is changing, and whether a change in prescriptive eyewear is needed. Eye exams also help to ensure that vision impairments do not interfere with daily activities.
Corrective concave (minus) lenses in the form of glasses or contact lenses are prescribed to help focus light more precisely on the retina, where a clear image will be formed. Refractive surgery, or LASIK, is also a viable option in many instances. Dr. Velasco can help decide which of these procedures is right for you. Depending on the degree of myopia, glasses or contact lenses may be needed all of the time for clear vision. If the degree of impairment is slight, corrective lenses may be needed only for activities that require distance vision, such as driving, watching TV or in sports requiring fine vision.
NEARSIGHTEDNESS IN CHILDREN
School age children may have vision problems ranging from mild to severe. When problems are suspected, it is important that the child have a comprehensive eye health examination to determine the nature of the problem and to rule out serious eye diseases. When vision conditions are treated properly, the child will enjoy the best possible sight.
To help a child cope with nearsightedness:
Avoid referring to the child’s eyes as “bad eyes;” instead tell the child that his or her eyes just bend light differently and corrective lenses are needed to help focus light rays.
Ensure that they understand that nearsightedness rarely disappears and that wearing spectacles may be necessary in the long-term, but that this is not a disease.
Use illustrations and simple explanations to help the child understand how a differently-shaped eyeball may result in his or her being nearsighted.
Make the occasion of selecting new frames for lenses a fun time.
Consider contact lenses as an option.
Do not restrict the child’s activities because of poor vision.
Include the child in discussions about his or her eyesight. Encourage the child to verbalize concerns about the adjustment to rapidly changing vision.
Astigmatism is a vision condition in which light entering the eye is unable to be brought to a single focus,
resulting in vision being blurred at all distances.
Astigmatism is one of a group of eye conditions known as refractive errors. Refractive errors cause a
disturbance in the way that light rays are focused within the eye. With astigmatism, light rays are focused in such
a way that both nearby and faraway objects may appear blurry. Astigmatism often occurs with nearsightedness
and farsightedness, conditions also resulting from refractive errors.
If you experience a distortion or blurring of images at all distances — nearby as well as far — you may have
astigmatism. Even if your vision is fairly sharp, headache, fatigue, squinting and eye discomfort or irritation may
indicate a slight degree of astigmatism. A thorough eye examination by Dr. Velasco, including tests of near vision,
distant vision and vision clarity, can determine if astigmatism is present. Astigmatism is not a disease nor does
it mean that you have “bad eyes.” Usually, it simply means that you have a variation or disturbance in the shape
of your cornea.
WHAT CAUSES ASTIGMATISM?
Normally the cornea, the front window of the eye, is smooth (like a baseball) and equally curved in all directions.
This causes light entering the eye to be focused equally on all planes, or in all directions. In astigmatism, the
front surface of the cornea is curved more in one direction than in the other (like an American football or rugby
ball). With the cornea being irregularly shaped, the light hitting the more curved surface comes to a focus before
that which enters the eye through the less curved surface. Thus, the light is focused clearly along one plane, but
is blurred along the other so only part of anything being looked at can be in focus at any time.
This abnormality may result in vision that is much like looking into a distorted, wavy mirror. The distortion results
because of an inability of the eye to focus light rays to a point.
Not all corneas are perfectly curved, just as sets of teeth are seldom perfectly aligned. The degree of variation
determines whether or not you will need a correction for the astigmatism. If the corneal surface has a high
degree of variation in its curvature, light refraction may be impaired to the degree that corrective lenses are
needed to help focus light rays better.
WHO DEVELOPS ASTIGMATISM?
Astigmatism is very common. Some experts believe that almost everyone has some degree of astigmatism,
often from birth, which may remain the same throughout life. However, only individuals with moderate to highly
astigmatic eyes usually need corrective lenses.
The exact reason for differences in corneal shape remains unknown, but the tendency to develop astigmatism is
inherited. For that reason, some people are more prone to develop astigmatism than others.
HOW IS IT DIAGNOSED?
Astigmatism is diagnosed in the course of a thorough eye examination by Dr. Velasco. Keep in mind that in children, astigmatism is often not detected during routine eye screenings in school. For this reason, children should be examined by Dr. Velasco as often as recommended.
HOW IS IT TREATED?
If the degree of astigmatism is slight and no other problems of refraction, such as nearsightedness or
farsightedness, are present, corrective lenses may not be needed. If the degree of astigmatism is great enough
to cause eyestrain, headache, or distortion of vision, prescription lenses will be needed for clear and
The corrective lenses needed when astigmatism is present are called “toric” lenses and have an additional
power element called a cylinder. They have greater light-bending power in one axis or direction than in the
others. Precise tests will be made during your eye examination to determine the ideal lens prescription.
Today, contact lenses are also a great option for the majority of those patients with astigmatism. Hard lenses,
soft lenses, and even hybrid combination lenses work well. Those that have been told that they could not wear
contact lenses in the past due to astigmatism are finding it easier to wear lenses and be happy with clear,
LASIK and other refractive surgeries are also a great option.
Since there are so many options, Dr. Velasco will help you decide which one of these procedures is best for you. Astigmatism may increase slowly over time. Yearly eye examinations by Dr. Velasco can help to ensure that
proper vision is maintained.
Hold the book up close and the words appear blurred. Push the book farther away, and the words snap back into
sharp focus. That’s how most of us first recognize a condition called presbyopia, a name derived from Greek words meaning “old eye.” Eye fatigue or headaches when doing close work, such as sewing, knitting or painting, are also common symptoms. Because it is associated with aging, presbyopia is often met with a groan — and the realization that reading glasses or bifocals are inevitable
WHAT CAUSES PRESBYOPIA?
As we age, body tissues normally lose their elasticity. As skin ages, it becomes less elastic and we develop wrinkles. Similarly, as the lenses in our eyes lose some of their elasticity, they lose some of their ability to change focus for different distances. The loss is gradual. Long before we become aware that seeing close up is becoming more difficult, the lenses in our eyes have begun losing their ability to flatten and thicken. Only when the loss of elasticity impairs our vision to a noticeable degree do we recognize the change.
Recent research suggests that presbyopia occurs when the lens keeps growing as people get older and the ligaments become too slack for the muscles to work properly. This finding contrasts with the traditional view that aging cause the focusing muscles to become weaker and the lens to become more inflexible.
HOW DOES THE LOSS OF ELASTICITY AFFECT SIGHT?
The crystalline lens plays a key role in focusing light on the retina. When we are young, the lens is flexible. With the help of tiny ciliary muscles, it changes shape, or accommodates, for both near and distant objects by bending or flattening out to help focus light rays. As we age, the lens becomes stiffer. Changing shape becomes more difficult. Not only does focusing on near objects become more difficult, the eye is also unable to adjust as quickly to rapid changes in focus on near and distant objects.
The flexibility of the lens begins to decrease in youth. The age at which presbyopia is first noticed varies, but it usually begins to interfere with near vision in the early 40’s. Presbyopia affects everyone and there is no known prevention for it.
HOW IS THE PROBLEM DIAGNOSED AND TREATED?
An accurate, thorough description of symptoms and a comprehensive eye health examination, including a testing of the quality of your near vision, are necessary to diagnose presbyopia.
Usually, the treatment for presbyopia is prescription eyeglasses to help the eye accommodate for close-up work. Prescription lenses (reading glasses) help refract light rays more effectively to compensate for the loss of near vision. If you do not have other vision problems, such as nearsightedness or astigmatism, you may only need glasses for reading or other tasks performed at a close range. If you have other refractive errors, such as nearsightedness, bifocal or progressive addition lenses (in which the power of the lens changes gradually towards the bottom to allow reading, without the reading portion of the bifocal lens being obviously visible) are often prescribed.
CAN I STILL WEAR CONTACT LENSES?
Yes, you have three options with contact lenses: Bifocal contact lenses, monovision, and normal distance contact lenses with reading glasses. Generally, bifocal contact lenses are not as successful as the normal “single vision” ones.
WHAT LENS OPTION WILL WORK BEST FOR ME?
You will be asked a number of questions about your usual lifestyle or daily activities – to help determine the solution most suited to your needs. For instance, if you are a librarian, your needs will be significantly different from those of a truck driver or office worker.
Presbyopia is a gradual change, happening over a number of years so your prescription will need to be updated periodically. Changes are best made at your regular eye examination rather than after the need for change starts to cause you difficulties.
Are contacts right for you?
The vast majority of people requiring vision correction can wear contact lenses without any problems. New materials and lens care technologies have made today’s contacts more comfortable, safer and easier to wear.
Consider the questions and answers below to help assess whether they’re a choice you should consider.
Contact lens wear may be difficult if:
Your eyes are severely irritated by allergies;
You work in an environment with lots of dust and chemicals;
You have an overactive thyroid, uncontrolled diabetes, or severe arthritis in your hands; or
Your eyes are overly dry due to pregnancy or medications you are taking.
After a thorough eye examination, your suitability for contact lenses and the specific contact lens option that best meets your requirements will be determined.
What are the advantages of wearing contact lenses?
Many wearers feel that contact lenses show their eyes in a better light or don’t like the appearance of eyeglasses.
Better vision correction due to the reduced obstruction from eyeglass frames.
They provide excellent peripheral vision.
No fogging up in warm rooms.
No splattering during rain showers.
Less hassle as they don’t get in the way during sports and other recreational activities.
What are the disadvantages?
Contact lenses require getting used to. New soft lens wearers typically adjust to their lenses within a week. Rigid lenses generally require a somewhat longer adjustment period. Except for some disposable varieties, almost all lenses require regular cleaning and disinfection, a process that, although requiring only a few minutes, is more than some people want to undertake. Some types of lenses increase your eyes’ sensitivity to light.
What lifestyle do you lead? What kind of work do you do?
For those involved in sports and recreational activities, contact lenses offer a number of advantages. In addition to providing good peripheral vision, eliminating the problem of fogged or rain splattered lenses, and freeing you from worries about broken glasses, contact lenses also mean you can wear non-prescription protective eye wear. Looking sideways through the lenses of glasses leads to prismatic effects because you are not looking through their centers. Your eyes have to coordinate differently to cope with this. This does not happen with contact lenses because you always look through the centers of the lenses as they move with your eye movements. Your occupation and work environment should also be taken into consideration. People whose work requires good peripheral vision may want to consider contacts. Those who work in dusty environments or where chemicals are in heavy use are likely to find spectacles more comfortable.
Do you like wearing glasses?
Do you like the way glasses feel? Do you like how you look in them? No longer is it really necessary to choose between either contacts or glasses. Some of today’s contacts are so easy to wear that you can use them intermittently — for special occasions, while participating in sports or to match your fashions.
New single-use, one-day disposable lenses are comfortable and do not require cleaning. They may be easily interchanged with glasses.
How contact lenses correct vision
Contact lenses are designed to rest on the cornea, the clear outer surface of the eye. They are held in place mainly by adhering to the tear film that covers the front of the eye and, to a lesser extent, by pressure from the eyelids. As the eyelid blinks, it glides over the surface of the contact lens and causes it to move slightly. This movement allows the tears to provide necessary lubrication to the cornea and helps flush away debris between the cornea and the contact lens. Contact lenses are optical medical devices, primarily used to correct nearsightedness, farsightedness, astigmatism and presbyopia. In these conditions, light is not focused properly on the retina, the layer of nerve endings in the back of the eye that converts light to electrochemical impulses. When light is not focused properly on the retina, the result is blurred or imperfect vision.
When in place on the cornea, the contact lens functions as the initial optical element of the eye. The optics of the contact lens combine with the optics of the eye to properly focus light on the retina. The result is clear vision.
Contact lenses aren’t just for seeing better. They’re for looking better too. In fact, some people who don’t even need vision correction wear tinted contact lenses as a way to change their look. Today’s tinted lenses allow you to enhance your natural eye color — making the blue bluer or the green greener — or change it altogether.
Three categories of tinted contact lenses are available:
Cosmetic enhancement tints are designed to enhance your natural eye color. These translucent lenses are best for light-colored eyes (blues and greens, hazels and grays). When wearing these tints, the color of your eye becomes a blend of the lens tint and your natural eye color.
Opaque, or “cosmetic,” tints change the color of dark eyes. The pattern on the lens, which is colored, overlies the colored part of your eye. The result is a natural look.
Visibility tints are very pale, but are colored enough to make the contact lens visible during handling without any effect on eye color.
With tinted lenses, you accomplish two goals at once: seeing better and looking better.
Lens Care Solutions
When you are fitted for contact lenses a particular lens care system is recommended — a group of products to clean, disinfect and make your lenses safe and comfortable for wear. Since different systems use different types of chemicals, it is not advisable to mix or substitute solutions from other systems. Doing so could lead to discolored lenses, eye discomfort or eye injury. In particular, rigid lens solutions should not be used to clean or disinfect soft lenses as the chemicals can damage the soft lens material.
Soft contact lens care systems
Regardless of how they are packaged, most lens care systems include products that perform six different functions. Some systems combine two or more functions into one product while others keep them separate. The functions required are dependent upon the type of lens regimen and your eyes and will be discussed with you as part of a contact lens training program.
The six different functions performed by soft lens care systems are:
Daily cleaning to remove debris accumulated and adhering loosely to the lens. This debris, if not removed, can eventually make the lenses uncomfortable, interfere with vision and reduce the ability of the disinfecting solution to kill potentially harmful microorganisms. In addition, the cleaning solutions perform the first step in the disinfection process.
Disinfecting to kill growing forms of microorganisms (bacteria, fungi, and viruses) on the lenses.
Rinsing and storing requires the use of an ophthalmic isotonic saline solution or may be performed with some types of disinfectant solution. Most saline solutions are not suitable for storage of lenses, as they do not contain anything to kill or prevent the growth of microorganisms.
Comfort or lubricating drops are used to provide refreshment for dry eyes, in conditions of low humidity or for added comfort near the end of the wearing day.
Protein removal removes stubborn protein deposits and, with daily cleaning and disinfection, helps restore a clean, fresh contact lens surface. Protein removal is generally not required for planned replacement lenses, which are replaced before the deposits can cause difficulties.
Rigid Gas Permeable (RGP) contact lens care systems. RGP lenses must be cleaned and disinfected for safe and comfortable wear.
The lens care system recommended will include a group of products designed to work together to clean, rinse, disinfect and remove protein deposits and to re-wet your eyes if they become dry during contact lens wear. It is important to use only those systems designed specifically for rigid gas permeable lenses. They are formulated with disinfectants and preservatives proven to work best with the material of which your lenses are made. If you wish to change your lens care regimen or to try a new lens care product, it is best to discuss this first, even if only by telephone, to ensure that you select products that are compatible with your eyes and will work well.
Types of Contacts
onfused about contacts? Advances in contact lens technologies have created many options in addition to hard and soft lenses. Today, contact lenses are likely to be described in one or several of the following ways.
By their prescribed wearing period (the time that the lenses are left in the eyes):
Daily wear (up to 18 hours)
Extended wear (overnight use, up to seven days)
By their replacement schedule (the time interval for replacing lenses):
Planned – frequent replacement: 1 month, 1-2 weeks; daily disposable
Unplanned, or conventional, replacement – no specific time schedule before lenses are replaced
By the type of vision correction for which they are designed:
Spherical (for near – or farsightedness – myopia or hypermetropia)
Toric (for astigmatism)
Bifocals (for presbyopia)
By the type of tint they have:
Tinted to improve handling only
Tinted to enhance your eye color (for light-color eyes)
Tinted to change your eye color (opaque tints for light or dark eyes)
Clear – without tints
Of course, contact lenses are also still described by the basic type of material of which they are made:
Rigid Gas Permeable
By wearing period:
Daily wear: lenses prescribed for daily wear are to be worn only during waking hours, usually up to a maximum of 18 hours. Daily wear lenses are removed at night and cleaned and disinfected after each removal.
Extended wear: these lenses may be worn on an overnight basis for up to seven consecutive days (six nights). You should wear your lenses on an extended wear basis only on the advice of your optometrist.
Extended wear lenses generally have a higher water content or thinner center thickness than other lenses and permit more oxygen to reach the eye. However, their use has been linked to a higher incidence of eye problems. Extended wear lenses need to be cleaned and disinfected at recommended intervals or discarded after use.
By replacement period
Contact lens are often prescribed with a specific replacement schedule suitable to your specific needs. Planned (or Frequent) Replacement contacts are disposed of and replaced with a new pair according to a plannedschedule. Unplanned replacement lenses (often called conventional lenses) are not replaced according to a pre- determined schedule. They are typically used for as long as they remain undamaged, usually around 12 months for soft lenses.
Why replace lenses frequently?
Almost immediately after they are inserted, contact lenses begin attracting deposits of proteins and lipids. Accumulated deposits, even with routine lens care, begin to erode the performance of your contacts and create a situation that presents a greater risk to your eye health.
A specific replacement schedule helps to prevent problems before they might occur. Contact lens wearers, in turn, enjoy the added comfort, convenience and health benefits of a planned replacement program. Planned replacement lenses are generally a thinner design or are made of different, more fragile materials with a higher water content than unplanned replacement or conventional contact lenses.
Based on a complete assessment of your needs, a prescription for planned replacement lenses may call for replacement:
Every 1-2 weeks
Except for daily disposables, planned replacement lenses require cleaning and disinfection after each period of wear unless they are discarded immediately upon removal. Planned replacement lenses can be worn as daily wear — removed before sleep — or as extended wear, if recommended by your practitioner.
By type of vision correction required
Contact lenses may be identified by the type of refractive error they are designed to correct.
Spherical contact lenses for nearsightedness (myopia) and farsightedness (hypermetropia);
Toric contact lenses for astigmatism;
Bifocal lenses for presbyopia, the loss of ability to focus on reading or close-up activities.
As an alternative to special bifocal contact lenses, many practitioners use a system called monovision where one eye is fitted with a distance lens and the other with a reading lens. Approximately two-thirds of patients adapt to this type of contact lens wear.
By type of tint
Contact lenses may be described as clear or tinted. Tints are used to make lenses more visible during handling, or for therapeutic or cosmetic reasons. Tints can enhance eye color, or change it altogether.
Three categories of tinted contact lenses are available:
Cosmetic enhancement tints are translucent and are designed to enhance your natural eye color. They are best for light-colored eyes (blues, greens, light hazel or grays). When wearing these tints, the color of your eye is a blend of the lens tint and your natural eye color and iris pattern.
Opaque or “cosmetic” tints change the color of your eyes whether they are dark or light. The pattern on the lens, which is colored, overlies the colored part of your eye, resulting in a color with a natural look.
Visibility tints are very pale, colored just enough to make the contact lens visible while you are handling it. They usually have no effect on eye color.
Soft VS RGP Lenses
Below is a brief comparison of soft and Rigid Gas Permeable (RGP) contact lenses. A thorough eye examination and a better understanding of your specific vision requirements will help determine the best options for you.
Soft contact lenses
Greater initial comfort than hard or rigid gas permeable (RGP) lenses.
Shorter adaptation period for new wearers.
Ideal for intermittent wear.
Less susceptible to the intrusion of foreign objects under the lens, such as dust.
Less sensitivity to light than with hard or RGP lenses.
Rarely fall out of the eye, making them ideal for sports, particularly contact sports such as football or basketball.
Available in tinted versions.
Less durable than hard or RGP lenses.
May dry out, causing discomfort for some, especially under a hair dryer, in hot rooms, or in windy, dry weather.
More involved lens care, especially for conventional soft lenses.
Susceptible to more protein or lipid deposits, that reduce lens performance in the long term.
May absorb chemicals from the environment, which can cause irritation.
Rigid Gas Permeable (RGP) lenses
RGP lenses are, as the name implies, rigid, but the plastics of which they are made are somewhat more flexible than hard lenses. Newer RGP lenses offer the advantage of allowing more oxygen to pass through to the eye.
Sometimes they are referred to as “Oxygen Permeable Lenses”. They are available in daily wear and extended wear options.
Correct most corneal astigmatism.
Good handling characteristics.
Less initial comfort than soft lenses.
Longer adaptation period required than soft lenses.
More easily dislodged.
Can scratch and break.
Intermittent wear less feasible.
Teens and Contacts
Oh, the pressure! Get great grades, excel in at least one sport, play a musical instrument, work part-time, hang out with friends — and always, always look cool. If you’re a teenager today, much is expected. But what to do if suddenly you can’t make out the writing on the blackboard, you can’t see the ball until it’s practically in your hands, or you have to squint to read the notes? What to do — and still look cool?
Try contact lenses. Not that glasses can’t be fashionable. But for today’s active teenagers, contacts are a perfectfit. What your parents may not know is that today’s lenses are more comfortable and easier to care for than those of a decade ago. Plus, there are more types of contacts, from disposables to toric (especially for people with astigmatism), from which to choose. In other words, there are almost certainly lenses to fit your individual needs.
When can you begin wearing contact lenses?
Even pre-teens can handle contacts. A three-year study* conducted by the Indiana University School of Optometry found children ages 11-13 able to handle contacts well and understand the use of their care systems to maintain clean, comfortable lenses. When to begin contact lens wear can only be determined in conjunction with your eye care practitioner.
What are the advantages of contact lenses over eyeglasses? Glasses can get in the way, especially in sports, cheerleading, dance or other exercise. Not contact lenses. Nor are there rims to interfere with your side, or peripheral, vision.
When you’re active, contact lenses don’t steam up or slide down your nose. Plus, they eliminate that annoying pressure behind your ears.
Fiction or fact? Truths about contact lenses.
FICTION: Teen eyes are not “mature enough” for contacts.
FACT: Most eye care professionals agree that by age 13, even as early as age 11, most eyes are developed enough for contact lenses. An eye exam will confirm whether contacts can be worn or not.
FICTION: Contacts fall out a lot.
FACT: They fell out more often when the only ones available were hard lenses. Soft lenses conform to the shape of the eye, are larger in diameter and are tucked under the eyelids, so they usually don’t move out of place or fall out. Plus, they’re usually more stable than glasses, especially for sports.
FICTION: Contact lenses are expensive.
FACT: Not! The price of contact lenses is comparable to that of an average pair of eyeglasses.
FICTION: Contact lenses are hard to care for.
FACT: Not at all. Today’s lens care systems are easy and quick to use. Contacts can be ready to wear in just five minutes.
FICTION: Contact lenses are not safe to wear for sports.
FACT: Except for water sports, contacts are very safe. They can’t be broken or knocked off the face and they provide unobstructed peripheral vision.
Ask your parents to make an appointment to assess your ability to wear contacts. If he or she gives thumbs-up, then try a pair. Wearing lenses is the best way to find out if you and contact lenses were made for each other.
WHAT IS AMBLYOPIA?
Amblyopia (lazy eye) is the loss or lack of development of vision in an eye that is unrelated to any eye health problems. The brain does not acknowledge the images seen by the amblyopic eye. Reduced vision due toamblyopia is not correctable with lenses alone.
WHO IS LIKELY TO DEVELOP AMBLYOPIA?
Amblyopia is the result of poor early visual development, and as such, usually occurs before the age of eight. Infants born prematurely or with low birth weight are at a greater risk for the development of the condition.
WHAT CAUSES AMBLYOPIA?
Amblyopia usually results from a failure to fully use both eyes together. It can be caused by the presence of strabismus (crossed-eyes), unequal refractive errors (farsightedness or nearsightedness), or a physical obstruction of vision (cataract). If there is a large enough difference in the degree of nearsigtedness, farsightedness or astigmatism between the two eyes, or if the eyes are crossed, the brain learns to ignore one image in favor of the other.
HOW DOES AMBLYOPIA AFFECT MY VISION?
Normally, the images sent by each eye to the brain are very similar. When they differ too much, the brain learns to ignore the poor image sent by one eye and “sees” only with the good eye. The vision of the eye that is ignored becomes weaker from disuse.
IS THE AMBLYOPIC EYE BLIND?
The amblyopic eye is never blind in the sense of being entirely without sight. Amblyopia affects only the central vision of the affected eye. Peripheral awareness will remain the same.
WHAT ARE SIGNS OF AMBLYOPIA?
Amblyopia usually produces few symptoms. It may be accompanied by crossed-eyes or a large difference in the refractive error between the two eyes. A child may also exhibit noticeable favoring of one eye and may have a tendency to bump into objects on one side.
A comprehensive optometric examination can determine the presence of amblyopia. The earlier it is diagnosed, the greater the chance for a successful treatment. Since amblyopia usually occurs only in one eye, the good eye takes over and the individual is generally unaware of the condition. That is why it is important to have your child’s vision examined at six months of age, at age three and again before he or she enters school.
HOW IS AMBLYOPIA TREATED?
Treatment that includes patching the good eye may help the amblyopic eye to improve. In addition, to help improve vision function, vision therapy techniques may be used. Eyeglasses or contact lenses may be prescribed to correct any refractive errors. A better outcome is achieved the earlier that amblyopia, or a condition that could lead to amblyopia, is diagnosed and treatment is initiated.
IS AMBLYOPIA PREVENTABLE?
Early detection and treatment of amblyopia and significantly unequal refractive errors can help to reduce the chances of one eye becoming amblyopic. Amblyopia is a challenge because it can limit the occupational and leisure activities one can do. Activities requiring good depth perception may be difficult or impossible to perform. In addition, should your good eye become injured or develop vision problems, you may have difficulty maintaining your normal activities.
WHAT IS COLOR DEFICIENCY?
Color deficiency occurs when the ability to distinguish certain colors and shades is less than normal. The term “color blind” is often used, but usually incorrectly. Only a very small number of people are completely unable to identify any colors.
WHAT CAUSES COLOR DEFICIENCY?
Color Deficiency is usually inherited, but can also result from certain diseases, trauma or as a side effect of certain medications. It happens when the color-sensitive cone cells in the retina of the eyes do not properly pick up or send correct color signals to the brain.
WHAT TYPES OF COLOR DEFICIENCY EXIST?
In lay terms, there are two major types. Red-green deficiency is by far the most common and results in the inability to distinguish certain shades of red and green. Blue-yellow deficiency is less common and affects the perception of blue and yellow colors. In very rare cases, color deficiency exists to an extent that no colors can be detected. This person sees all things in shades of black, white and gray.
HOW IS COLOR DEFICIENCY DETECTED?
People who are color deficient are often unaware of their condition. They assume that everyone sees things the way they do. As a result, a complete optometric examination, including a test for color vision, is recommended. A basic test for color deficiency is relatively simple and typically involves viewing a series of colored designs or objects. Dr. Velasco always includes a color vision examination as part of the comprehensive eye testing done at iFocus Vision Center.
WHEN SHOULD A PERSON BE TESTED FOR COLOR DEFICIENCY?
Every child should be checked for color deficiency by at least age five. It is important to detect color deficiency early because color coded learning materials are used extensively in the primary grades. In addition, color deficiency may affect the career path of an individual, since the ability to distinguish colors is an important aspect of some jobs, such as pilots, electricians, some military personnel, police officers and others.
CAN COLOR DEFICIENCY BE CURED?
Unfortunately, a cure for color deficiency has not yet been discovered. A person with color deficiency can, however, be taught to adapt to the inability to distinguish colors. For example, you can be taught to recognize the brightness and location of a traffic light rather than the color itself. It is sometimes possible to increase the ability to distinguish colors with the use of special filters. A special red tinted contact lens in one eye and other devices are used, in some cases, to aid persons with certain color deficiencies.
Your school-age child’s eyes are constantly in use in the classroom and at play. When his or her vision is not functioning properly, learning and participation in recreational activities can suffer. Good vision involves many different skills working together to enable your child not only to see clearly but also to understand what he or she sees.
Those skills include:
Near vision – the ability to see clearly and comfortably at 13-16 inches, the distance at which school deskwork should be performed.
Distance vision – the ability to see clearly and comfortably at 10 feet or more.
Binocular coordination – the ability to use both eyes together.
Eye movement skills – the ability to aim the eyes accurately, and move them smoothly across a page and
quickly and accurately from one object to another.
Peripheral awareness – the ability to be aware of things to the side while looking straight ahead.
Eye/hand coordination – the ability to use the eyes and hands together.
If any of these or other vision skills is lacking or not functioning properly, your child’s eyes have to work harder. This can lead to blurred vision, headaches, fatigue and other eyestrain symptoms.
WHY THROUGH EYE EXAMS ARE IMPORTANT
Don’t assume your child has good vision because he or she passed a school vision screening. A 20/20 score means only that your child can see at 20 feet what he or she should be able to see at that distance. It does not measure any of the other vision skills needed for learning. Vision screenings are important but they should not be substituted for a thorough vision examination.
THINGS YOU CAN DO
There are things you can do to help ensure that your child’s vision is ready for school each year and to relieve the visual stress of schoolwork.
Be alert for symptoms that may indicate your child has a vision problem. Note if your child frequently:
Loses his or her place while reading.
Avoids close work.
Holds reading material closer than normal.
Tends to rub his or her eyes.
Turns or tilts their head to use one eye only.
Makes reversals when reading or writing.
Uses a finger to maintain their place while reading.
Omits or confuses small words when reading.
Performs below potential.
Closes one eye while reading.
Make sure your child’s homework area is evenly lighted and free from glare. Furniture should be the right size for proper posture. During periods of close concentration, have your child take periodic breaks. Rest breaks are also recommended when your child is using a computer or playing video games.
To make TV viewing easier on your child’s eyes:
Be sure the room has overall soft lighting.
Place the set to avoid glare and reflections.
Watch from a distance at least five times the width of the screen.
Be sure your child’s hours away from school include time for exercise and creative play. Both can help keep
his or her vision skills functioning properly.
Teach your child eye protection through these safety rules:
Keep away from the targets of darts, bows-and-arrows, air guns and missile-throwing toys.
Don’t shine laser pointers into anyone’s eyes. Teach them laser pointers are not toys.
Don’t run with or throw sharp objects.
Wear safety goggles when using chemistry sets, power tools and household and yard chemicals. (Note:
Be certain your child is mature enough to handle these items safely, and provide proper supervision.)
THOROUGH VISION CARE IS IMPORTANT
Because a change in vision can occur without you or your child realizing it, have your child’s eyes examined every year.
A thorough eye examination should include:
A review of your child’s health and vision history.
Tests for nearsightedness, farsightedness, astigmatism, color perception, lazy eye, crossed-eyes, eye
coordination, depth perception and focusing ability.
An eye health examination.
IF YOUR CHILD NEEDS HELP
After assessing your child’s test results, glasses, contact lenses or vision therapy may be prescribed. He or she may also recommend preventive measures, such as mild prescription lenses to be worn only when doing schoolwork or watching television. These may help relieve stress on your child’s eyes. Your care and concern for your child’s vision can enrich his or her future while helping develop eye care habits for a lifetime of good vision. About 80 percent of all babies are born farsighted — able to see objects clearly at a distance but less clearly close. Some five percent are born nearsighted, or unable to see objects at a distance clearly.
Approximately 15% are born with nothing wrong with the refractive parts of the eye — the cornea and crystalline lens which bend light and focus it properly on the retina.
Farsightedness usually decreases as a child ages, typically normalizing to a negligible value by the age of 7-8.
After a child grows and the incidence of farsightedness decreases, that of nearsightedness increases. Many school-age children and teens first discover they are nearsighted when they have difficulty reading the writing on the board at school. Nearsightedness usually occurs before age 25.
If you see two of whatever you are looking at, you may have a condition known as double vision, also referred to as diplopia. Double and blurred vision are often thought to be the same, but they are not. In blurred vision, a single image appears unclear. In double vision, two images are seen at the same time, creating understandable confusion for anyone who has it.
WHAT CAUSES DOUBLE VISION?
There are two possible causes. Failure of both eyes to point at the object being viewed, a condition referred to as “strabismus” or “squint”. In normal vision, both eyes look at the same object. The images seen by the two eyes are fused into a single picture by the brain. If the eyes do not point at the same object, the image seen by each eye is different and cannot be fused. The result is double vision. Why might eyes not point in the same direction? Possibly because of a defect in the muscles which control the movement of the eyes or in the control of these muscles through the nerves and brain.
Refractive Light from an object is split into two images by a defect in the eye’s optical system. Cataracts may cause such a defect.
Strabismus is a more common cause of double vision than is refractive defect.
WHAT ARE ITS IMPLICATIONS?
Double vision can be extremely troubling. The brain acts to alleviate the discomfort by suppressing, or blanking out, one of the images. In young children, if this suppression persists over a continued length of time, it can lead to an impairment of the development of the visual system. The suppressed eye may get to the point where it is unable to see well, no matter how good the spectacle or contact lens correction. Doctors call this condition “amblyopia”. Since it is a result of a defect in the interpretive mechanisms of the eye and brain, it is more difficult to treat than a refractive condition (one having to do with the eye’s ability to bend light).
HOW IS IT TREATED?
Treatment of double vision consists of eye exercises, surgical straightening of the eye or a combination of the two. Therapy is aimed at re-aligning the squinting eye where possible without surgery and re-stimulating the part of the visual pathway to the brain that is not working correctly.
If the double vision is due to the presence of cataracts, referral for possible cataract surgery will be undertaken.
Flashes and Floaters
Do you occasionally see specks or threadlike strands drifting across your field of vision? Then, when you try to look at them, do they seem to dart away? If so, you’re seeing what eye care practitioners call spots or floaters.
While almost everyone sees a few spots at one time or another, they can occur more frequently and become more noticeable as you grow older. If you notice a sudden change in the number or size of spots, you should contact us right away so you can be sure they are not the result of a more serious problem.
WHAT ARE SPOTS OR FLOATERS?
Spots are small, semi-transparent or cloudy specks or particles within the eye that become noticeable when they fall within the line of sight. They may also appear with flashes of light. The inner part of your eye is made up of a clear, jelly-like fluid known as the vitreous. As time passes the jelly-like fluid gradually becomes more liquid in nature and cells and structural fibres detach and float around in this jelly, resulting in the floaters that we commonly observe.
When flashes of light occur causing spots to become noticeable, it can be a result of the jelly-like vitreous shrinking and pulling on the retina. This tugging action stimulates the retinal receptor cells to “fire,” causing the perception of light flashes.
CAN THESE SPOTS CAUSE BLINDNESS?
Most spots are normal and rarely cause blindness. But spots can indicate more serious problems. If you notice a change in the number and size of spots, a comprehensive eye examination is in order to determine the cause. On rare occasions, vitreous detachment can cause small tears or holes in the retina. The damaged part of the retina subsequently does not work properly and a blind or blurred spot in vision results. If untreated, retinal tears or holes can continue to worsen and severe vision loss can result if the retina becomes detached.
HOW ARE SPOTS DIAGNOSED?
In a comprehensive eye examination, your eyes will be evaluated with special instruments that allow an examination of the health of the inside of your eyes and possible observation of the spots. This is often done after special drops are put in your eyes to make the pupils larger (called dilation) to allow a larger view of the inside of your eyes. These procedures provide the relevant information to detect spots.
HOW ARE SPOTS TREATED?
While flashes and floaters are normally not serious or treatable, they can be symptoms or signs of either vitreous or retinal detachment. In either of these cases, treatment with lasers and/or surgical intervention may be necessary to preserve your vision. If you notice a sudden increase or change in the number and type of spots and floaters, contact us immediately.
How the eye works
Our ability to “see” starts when light reflects off an object at which we are looking and enters the eye. As it enters the eye, the light is unfocused. The first step in seeing is to focus the light rays onto the retina, which is the light sensitive layer found inside the eye. Once the light is focused, it stimulates cells to send millions of electrochemical impulses along the optic nerve to the brain. The portion of the brain at the back of the head interprets the impulses, enabling us to see the object.
Light, refraction and its importance.
Light entering the eye is first bent, or refracted, by the cornea — the clear window on the outer front surface of the eyeball. The cornea provides most of the eye’s optical power or light-bending ability. After the light passes through the cornea, it is bent again — to a more finely adjusted focus — by the crystalline lens inside the eye. The lens focuses the light on the retina. This is achieved by the ciliary muscles in the eye changing the shape of the lens, bending or flattening it to focus the light rays on the retina.
This adjustment in the lens, known as accommodation, is necessary for bringing near and far objects into focus. The process of bending light to produce a focused image on the retina is called “refraction”. Ideally, the light is “refracted,” or redirected, in such a manner that the rays are focused into a precise image on the retina. Most vision problems occur because of an error in how our eyes refract light. In nearsightedness (myopia), the light rays form an image in front of the retina. In farsightedness (hypermetropia), the rays focus behind the retina.
In astigmatism, the curvature of the cornea is irregular, causing light rays to focus to more than one place so that a single clear image cannot be formed on the retina, resulting in blurred vision. As we age, we find reading or performing close-up activities more difficult. This condition is called presbyopia, and results from the crystalline lens being less flexible, and therefore less able to bend light.
Since changing the apparent refraction of the eye is relatively easy through the use of corrective spectacle, contact lenses, or refractive surgery (like LASIK), many of the conditions that contribute to unclear vision can be readily corrected.
How do we make sense of light?
Even with the light focused on the retina, the process of seeing is not complete. For one thing, the image is inverted, or upside down. Light from the various “pieces” of the object being observed stimulate nerve endings — photoreceptors or cells sensitive to light — in the retina.
Rods and cones
Two types of receptors — rods and cones — are present. Rods are mainly found in the peripheral retina and enable us to see in dim light and to detect peripheral motion. They are primarily responsible for night vision and visual orientation. Cones are principally found in the central retina and provide detailed vision for such tasks as reading or distinguishing distant objects. They also are necessary for color detection. These photoreceptors convert light to electrochemical impulses that are transmitted via the nerves to the brain.
Millions of impulses travel along the nerve fibers of the optic nerve at the back of the eye, eventually arriving at the visual cortex of the brain, located at the back of the head. Here, the electrochemical impulses are unscrambled and interpreted. The image is re-inverted so that we see the object the right way up. This “sensory” part of seeing is much more complex than the refractive part — and therefore is much more difficult to influence accurately.
What is 20/20 Vision?
You may be pleased to hear that you have 20/20 vision and think you have perfect vision. But do you? Not necessarily. 20/20 only indicates how sharp or clear your vision is at a distance. Overall vision also includes peripheral awareness or side vision, eye coordination, depth perception, focusing ability and color vision.
20/20 describes normal visual clarity or sharpness measured at a distance of 20 feet from an object. If you have 20/20 vision, you can see clearly at 20 feet what should normally be seen at that distance. If you have 20/100 vision, it means that you must be as close as 20 feet to see what a person with normal vision can see at 100 feet.
Why do some people have less than 20/20?
The ability to see objects clearly is affected by many factors. Eye conditions like nearsightedness, farsightedness, astigmatism or eye diseases influence visual acuity. Most people with vision slightly below 20/20 function very well, whereas some people who have better than 20/20 vision feel that their vision is not satisfactory. Everybody’s visual expectations are different and satisfactory vision is far more complex than just being able to see 20/20.
If my vision is less than optimum, what can I do?
A comprehensive eye examination by Dr. Velasco will identify causes that may affect your ability to see well. She may be able to prescribe glasses, contact lenses or a vision therapy program that will help improve your vision. If the reduced vision is due to an eye disease, the use of ocular medication or other treatment may be needed.
Strabismus (Crossed Eyes)
Strabismus, sometimes known as “crossed eyes,” is a visual condition in which the eyes are not accurately aligned? One eye may be constantly or periodically turned in, out, up, or down in relation to the other eye. This lack of eye teaming may also occur under certain conditions such as when a person is tired or inattentive, looksin a certain direction or at a specific distance. The eye turn may alternate between eyes.
What causes strabismus?
Strabismus is caused by a lack of nerve muscle coordination, neurological or mechanical causes. Strabismus may also occur due to an eye injury, head injury, or stroke. It could also be caused by excessive farsightedness. Strabismus tends to be hereditary, but there are many factors involved.
Who is affected by strabismus?
Strabismus tends to occur either shortly after birth, around age three, or shortly after children start school. Some strabismus develops later in life due to a problem that has existed for many years, for which a person can no longer cocmpensate. Strabismus due to a stroke or injury can occur at any age.
Will a child outgrow strabismus?
Children almost never outgrow strabismus. It usually becomes more habitual over time and is frequently the cause of amblyopia (lazy eye) in which the vision in the deviated eye decreases due to lack of use. If left untreated, amblyopia may result in legal blindness of the affected eye.
What are the effects of strabismus?
Strabismus can initially cause double vision. To avoid double vision, the brain often disregards the image from one eye. This can result in permanent vision loss from amblyopia, and impairs the function of stereopsis (binocular depth perception), which can affect sports performance, driving, and many other activities of daily living.
How is strabismus diagnosed?
Strabismus can be easily missed. All children should have a comprehensive eye examination by Dr. Velasco at age six months, at age three, and before starting school. The earlier that strabismus is diagnosed, the greater likelihood of successful treatment.
How is strabismus treated?
Treatment of strabismus may include glasses, vision therapy, patching, and surgery. The specific treatment depends on the condition, its cause, its severity, and the age of the patient. Strabismus can often be corrected with excellent results if detected and treated early.