Glaucoma occurs when pressure inside the eyes builds because fluid to nourish eye tissue drains from the eyeball too slowly or suddenly stops draining.

Overview

Glaucoma (glaw-KOH-ma) is a group of diseases that cause vision loss or blindness by damaging the optic nerve responsible for transmitting impulses for sight from the retina to the brain. In most cases, this damage results from increased pressure in the eye that occurs when fluid that flows in and out of the anterior chamber to bathe and nourish nearby tissue drains out too slowly or suddenly stops draining.

This clear aqueous humor fluid circulates from behind your iris through the pupil, the dark opening in the center of your eye and into the space between your iris and your cornea. Besides providing nourishment, the aqueous humor also exerts a constant pressure to help maintain your eyes’ shape. To keep from building up in the eye, the fluid drains primarily through a “drainage angle,” a mesh of tissue where the cornea and iris meet. In a healthy eye, the excess fluid then flows into a channel and into small veins on the outside of your eye.

But when the drainage angle doesn’t function properly, the aqueous humor backs up to apply pressure on another fluid, the vitreous humor located behind the lens. This causes pressure inside the eyeball to increase. Unless controlled with medication or surgery, this can damage nerve fibers and other parts of the eye, causing a gradual loss in vision.

Glaucoma is the second leading cause of blindness in the U.S., and affects nearly 3 million Americans, most of whom are older than age 60. About 25 percent of people with glaucoma are considered legally blind; another 1 million others may be unaware they have this condition because the onset is so gradual. Glaucoma tends to run in families and is five times more common in African-Americans than Caucasians until middle age, when the risk tends to increase with age for all ethnic backgrounds.

There are two primary types of glaucoma:

• Open-angle glaucoma is the most common form, accounting for 60 to 70 percent of cases. It develops slowly and painlessly when there is too much aqueous humor or it doesn’t drain properly. “Open-angle” refers to the “drainage angle.” In primary open-angle glaucoma, there is too much aqueous being produced or it is not draining properly; in secondary open-angle glaucoma, other factors such as an anatomical variation to the eye, diabetes or medications can cause the pressure to increase in the same painless, progressive manner.
• Angle-closure glaucoma occurs in about 10 percent of cases. It is caused by a partial blockage of the angle and typically causes a sudden and dramatic increase in eye pressure that requires immediate medical attention. It is usually accompanied by some blurred vision, pain in or around the eye, redness, halos around lights and nausea and can result from using medications such as cold remedies, antidepressants and anti-nausea drugs.

There are also several rarer forms of the disease or syndromes that can lead to glaucoma:

• Congenital glaucoma, which typically affects children, is believed to result from an inherited developmental abnormality that blocks the eye drain. It typically occurs in infancy, childhood or adolesence.
• Secondary glaucoma, which usually results from trauma, chronic steroid use or disease.
• Normal-tension glaucoma occurs in people with normal intraocular pressure (IOP) that is below 22 mm Hg, but still develop optic nerve damage. (Meanwhile, others have high IOP but no optic nerve damage.)
• Pseudoexfoliation glaucoma occurs when both pigment and grayish material in the eye clog the angle meshwork.
• Pigment dispersion syndrome is a genetic disorder that causes glaucoma in up to 10 percent of people with this gene – usually people who are nearsighted.

Symptoms

Glaucoma often produces no initial symptoms. Vision is normal and there may be no pain. But as the disease progresses, you may first notice your peripheral vision gradually fading – especially near your nose. As the disease worsens, the field of vision narrows.

In open-angle glaucoma, you may develop “tunnel vision” — vision has narrowed so you see only what is directly in front of you, like looking through a tunnel. This type tends to affect both eyes, although you may have symptoms in just one eye first. Besides reduced peripheral vision, you may notice:

• Sensitivity to glare
• Trouble differentiating between varying shades of light and dark

In closed-angle glaucoma, you may have a sudden onset of:

• Blurred vision
• Halos around lights at night
• Eye redness or pain
• Headache
• Extreme weakness
• Nausea and vomiting

Prevention

Glaucoma cannot be prevented, but the earlier it is diagnosed, the greater the likelihood that it can be slowed down or even stopped with medication before vision is significantly impacted. Once detected, eye pressure can be controlled to reach acceptable lower levels and nerve damage may slow or stop, although the damage is not reversed.

Many people are aware of the “air puff” test or other tests used to measure eye pressure in an eye examination; glaucoma is also found during an eye examination through dilated pupils, in which your eyecare provider adminsters eye drops to enlarge the pupils to see more of the inside of the eye. Because the gradual vision loss may not be noticed until it is too late, regular eye examinations are important for everyone older than age 40, particularly if you:

• Have a family history of glaucoma, which increases risk about four-fold
• Are African-American
• Have diabetes or hypertension (high blood pressure)
• Take corticosteroids and other medications that increase the pressure in your eye
• Have experienced trauma to the eye, such as an eye injury.

Treatment

Medication is usually the first line of defense. Prescription eyedrops or pills help lower pressure inside the eyes by either slowing the flow of fluid into the eye or by improving drainage. Regular use of medication usually helps control increased pressure, but these drugs may not be as effective over time.

Surgery can also help fluid escape from the eye and thereby reduce the pressure, and is usually employed if medications are not helpful.

• Laser trabeculoplasty is the preferred treatment for open-angle glaucomas. In this procedure, a laser is used to widen the opening in the eye’s drainage network. Eyedrops are often following this surgery.
• Laser iridotomy is used to treat angle-closure glaucoma. In this procedure, a laser makes a hole in the iris to allow the aqueous flow.

If medication and laser surgery are not successful, conventional eye surgery may be necessary to create a new opening for fluid to leave the eye. Although done on an out-patient basis, it takes longer than laser surgeries and is consdiered to be riskier.

Matter floating inside the eye moves into the line of sight and appears as specks floating in front of our eyes.

Overview

Floaters (also called “spots”) are tiny clumps of gel or other semi-transparent matter that drift freely inside the vitreous, the jelly-like fluid that fills the inside of your eyes. In most cases, they are more bothersome than harmful – appearing as specks of varying shapes and sizes, or as strands, crystals, cobwebs or as fuzzy clouds that float about and may dart away when you attempt to look at them directly.

Floaters result from several causes: In childhood and early adulthood, most are pieces of blood vessels that were left suspended in the vitreous during fetal development, or small flecks of protein trapped during the formation of your eye. They may also result from specks of pigment on the muscle fibers attached to the iris, or particles caught in the tear layer in front of the eye.

More often, however, they result from the natural aging process, as the vitreous fluid deteriorates and crystal-like clumps form, a process that usually begins in your mid 40s. You may notice them more readily when looking at something bright, such as the sky or a white wall.

Floaters can affect anyone and are usually harmless, but tend to be more noticeable and frequent in people who are nearsighted, have undergone cataract surgery, or have injured or inflammed the eye. If you notice a sudden increase in floaters, see your eyecare provider, because they could indicate a more serious problem such as diabetic retinopathy, retinal hemorrhaging or the first signs of a detached retina.

Flashes, which appear as lightning streaks, shooting stars, fleeting white pinpoints or blasts of light, are false bursts of light produced by optic nerves of the retina. Most adults experience flashes after age 50, as the vitreous thickens as part of the normal aging process and begins to alternately pull away from and rub against the light-sensitive retina. They also appear in those prone to migraine headaches, sometimes right before the onset of a migraine, and can also result from head trauma or by blood vessel spasms in the brain. As with floaters, flashes should be checked by an eyecare provider to ensure they’re not the early sign of a more serious problem.

Symptoms

If you have floaters or flashes, you may notice:

• Spots, strands or shadowy shapes that appears to float or move
• Flashes of light that appear as streaks of jagged lines
• A migraine or headache may follow

Prevention

There is no way to prevent floaters or flashes, but if they occur suddenly or frequently, see your eyecare provider.

Treatment

Floaters and flashes are usually harmless and fade over time. When everyday floaters are bothering you, try looking up and down and from side-to-side. This stirs the vitreous fluid in your eyes, moving floaters away from your line of vision. Flashes caused by the vitreous separating from the retina are a normal part of aging and should subside in a few weeks or months.

There is no safe, reliable treatment to control or eliminate floaters or flashes. If you notice a sudden or dramatic increase in floaters or flashes that last more than 20 minutes, seek immediate medical attention, as this may indicate that you have retinal damage and left untreated, permanent vision loss may result. Surgery may repair damage if caught early.

In the rare case that vision is almost entirely clouded by floaters and floaters, a vitrectomy may be performed. In this procedure, the vitreous is replaced by clear saline solution to improve vision clarity. This is not usually recommended due to the high risk of total blindness associated with the procedure.

A farsighted eye is too “short,” causing light to converge behind the retina and blurring near vision.

Overview

Farsightedness, medically known as hyperopia (hi-pur-OH-pea-uh), refers to vision that is good at a distance but may be poor at close range. Farsightedness occurs when the eyeball is shorter than normal, as measured from front to back, or when the cornea has too little curvature. This reduces the distance between the cornea and retina, causing light to converge behind the retina, rather than on it.

Since we’re usually born with eyes that are too short, the majority of newborns are farsighted. As we grow, the “normal” eye gets longer and by 1 year, close vision is generally clear. Even when it doesn’t, farsightedness – also known as hypermetropia and long-sightedness – may go unnoticed until middle age – when the ciliary muscles controlling the lens begin to weaken and can no longer compensate for the limitation in near vision. This is why farsightedness, which is usually congenital, often isn’t apparent until the development of presbyopia.

Disease such as retinopathy, eye tumors and lens dislocation can also contribute to farsightedness, which is easily treated with corrective lenses and can also be managed with refractive laser surgery.

Symptoms

People who are farsighted typically have good distance vision, but may find it difficult to do close visual tasks, such as reading. Besides blurred vision or difficulty focusing during close activities such as reading or sewing, other symptoms include:

• Aching, burning, red or tearing eyes
• Eye fatigue
• Headaches or “brow” aches (occurring on the top of the eye), which can result from overworked ciliary muscles
• Poor hand-eye coordination
• Severely farsighted children may appear cross-eyed – a condition called accommodative esotropia that usually develops around age 3 and may be constant or intermittent.

Prevention

Farsightedness is largely believed to be inherited, with little evidence that enviromental factors cause its development. However, to avoid accentuating symptoms, your eyecare practitioner may recommend that you keep work areas well-lit and glare-free and give your eyes a break during close visual work by focusing on distant objects every 30 minutes or so.

Occasionally, conditions such as diabetes, lens dislocations and eye tumors can cause farsightedness. So if you experience any symptoms, see your eye doctor for a complete examination. Children should get a complete eye exam by age 3 and those with severe hyperopia need to be monitored to avoid the development of crossed eyes (strabismus) or lazy eye (amblyopia).

Treatment

If you are mildly farsighted, your eyecare practitioner may not recommend corrective treatment at all, since your ciliary muscles may be compensating by adjusting the shape of your lens to bring close vision into focus. However, if you are moderately or severely hyperopic or presbyopic, you have several treatment options:

• Corrective Lenses
  • Eyeglasses with convex lenses, which are thicker in the center and thinner on the edges, to bend light to converge further forward in the eye to reach the retina.
  • Contact lenses offer several options, such as soft lenses and rigid gas-permeable (RGP) lenses, which conform to the shape of the lens

• Laser surgery is effective for many people with farsightedness, but the long-term effects of these relatively new procedures are still being studied. Laser surgery, which still may result in the need for reading glasses, is generally not recommended for those under age 18 and carries risk of side effects such as increased sensitivity to glare, seeing halos around lights, poor vision, dry eye and others. Options include:
  • LASIK (laser in situ keratomileusis) is a procedure in which a surgeon slices a flap into the cornea and a laser removes some tissue from beneath the sliced area to reshape the cornea.
  • Photorefractive keratotomy (PRK) uses a laser beam to remove tissue from the outer surface of the cornea, reshaping it to improve its focus.

Dry eye can result from an imbalance in the components of tears.

Overview

Dry eye syndrome refers to a breakdown in the quantity or quality of tears to moisten, cleanse and protect the eyes. This is significant because with each blink, tears protect the surface of the eye, washing away dust and microorganisms. When this protective coating dries up, the eyes may feel “gritty” or burn, are more easily scratched and vulnerable to infection, and can be more sensitive to light. In extreme cases, vision can be blurred.

Dry eye syndrome is among the most common eye problems, and often results from the aging process, affecting nearly three in four people older than age 65. It is also more common among computer users, those with allergies to dust or pollen, contact lens wears, those with arthritis or certain immune disorders and those who work outdoors. Women are typically affected more often than men, as dry eye syndrome is triggered by hormonal changes such as post-menopause and during pregnancy or breast-feeding.

It also results from taking certain medications, including antidepressants, birth control pills, cold medications that act as antihistamines and decongestants, antihypertensives, antidiarrheals, acne medications and diuretics such as blood-pressure drugs. Dry eye is also a common but temporary side effect of LASIK, resulting from a disruption of the nerves of the cornea.

Dry eye occurs when there is a malfunction in one of more tear glands, or an imbalance in one or more of the three layers of tears:

• Oily layer, a thin outer tear layer produced in the meibomian and Zeis glands. These tiny glands line the edge of the eyelid and serve three purposes: To slow the evaporation of the watery middle layer; to increase surface tension so tears don’t overflow the eyelid; and to lubricate the eye during blinking.

• Watery layer, the middle layer of the tear that comes from lacrimal gland, which lies beneath a bone near the nose, and the glands of Krause and Wolfring, which are on the inner surface of the eyelids. This layer works to supply oxygen to the eye’s surface; to fight infection with natural antibiotics, such as lactoferrin and lysosomes; to act as a filling that smoothes the eye’s surface; and to wash away debris such as dead cells and dust.

• Mucous layer , the innermost layer of the tear that originates in the goblet cells, Henle’s crypts, and Glands of Manz. These glands are located in the conjunctiva, on the surface of the eye and inner eyelids. This thin layer helps tears glide evenly across the eye’s surface. Without it, the other layers of tears would form into tiny droplets instead of a smooth, even coating.

Some people with dry eye experience “reflex tearing.” After experiencing the discomfort of extremely dry eyes, a substantial amount of tearing suddenly occurs. For example, if you stare for a long period without blinking, your eyes will dry out and reflex tearing will kick in, causing a significant amount of tears to pour out. These tears contain unbalanced proportions of the different layers of tears.

Symptoms

Dry eye can cause any of the following:

• Burning or itching eyes
• A feeling of grittiness, as if there was sand in your eyes
• Difficulty in wearing contact lenses comfortably
• In some cases, you may experience increased sensitivity to light or excessive tearing
• In extreme cases, vision may appear blurred

Prevention

There are several ways to prevent the natural occurrence of dry eye to interrupt the quality of your life:

• If you use a computer regularly, take a 10-minute break every hour or so to give your eyes a rest.
• Use a humidifier when you are indoors, since dry heat and lack of humidity can be aggravating. This is especially important if you use a hair dryer or are exposed to chemical vapors, smoke, air conditioning or similar environmental conditions.
• Avoid wearing contact lenses when you experience symptoms. If you must wear contacts, be sure to lubricate eyes more frequently with artificial tear products.
• Wear protective eyewear when outdoor during windy days or around dust, pollen or other irritants.

Treatment

If you suspect that you have dry eye, see your eye doctor. Proper care will not only increase your comfort, it will protect your eyes. Your eyecare specialist can use simple tests to determine if your tears are drying up too quickly, and/or if your glands under your eyelids are not producing enough tears. If you have dry eye, your eye doctor can suggest many treatment options:

• Replace the natural tears with artificial tears. In most cases, the solution for dry eye is artificial tears. These are different from drops that remove redness and can be purchased over-the-counter. Moisturizing ointment may be prescribed, and certain homeopathic eyedrops may help the body increase tear secretion.

There are many types of artificial tears. If they are too thin, they will drain away or dry out too quickly. If too thick, they will blur vision. Some will have restrictions on the frequency of use. Read the labels carefully and try a few brands to determine which best suits your needs. Artificial tears usually solve the problem of mild to moderate dry eye. If they do not ease your symptoms, additional treatment may be necessary.

• Plug the eye’s drain. Your eyecare practitioner may suggest plugging the punctum, or drain opening, on your lower eyelids. Blinking creates a vacuum that sucks tears into these drains, from where they travel through nasolacrimal ducts to the throat. These tiny silicone punctual plugs are inserted manually to block drainage, and are recommended for moderate to severe dry eye.
• Seal the eye’s drain. Thermal cauterization will seal the punctum, blocking tear drainage permanently. In this procedure, using local anesthetic, the eye doctor inserts a hot wire into the punctum. The heat seals the drain. Scarring may occur, and the procedure is not reversible. A laser can be used to seal the punctum with less scarring, but there is a 20 percent change that the drain will reopen on its own.

Before considering medical approaches such as sealing and plugging the puncta, there are several “do-it-yourself” treatment methods you can try:

• Increase blinking. You may not be blinking enough, especially when working at a computer or reading for long periods of time. Try to blink more often, and take frequent breaks from using computers to avoid fatiguing your eyes.
• Massage your eyelids. A simple eyelid massage will stimulate the tear glands. Just place a warm washcloth over closed eyes and gently massage the upper eyelid against the brow bone for 5 to 10 seconds. Then massage the lower eyelid against the lower bone.
• Monitor your diet. Natural diuretics can dry your eyes (as well as the rest of your body). You may benefit from reducing or eliminating your intake of coffee, tea, cola, alcohol and chocolate. It’s also advised to drink at least 8 glasses of water each day to ensure proper hydration.
• Adjust your medications. Your healthcare provider may be able to lower the dosages or switching medications that can contribute to dry eye. These drugs include antidepressants, birth control pills, antihistamines, decongestants, antihypertensives, antidiarrheals, acne medications and diuretics such as blood-pressure drugs.
• Control your environment. Simple changes in your home or office may eliminate your dry eye symptoms, such as using a humidifier, installing incandescent lighting instead of fluorescent, turning down the thermostat, and avoiding smoke and allergens.
• Change your contact lens care regimen. When not disinfected or wetted properly, contact lenses can wick tears away from the eye. Be sure to follow all care instructions closely. Try switching brands of lens care products. Preservative-free products are usually gentler on your eyes.

Diabetic retinopathy damages the blood vessels that nourish the retina.

Overview

Diabetic retinopathy (dye-uh-BET-ick ret-in-AHP-uh-thee) is a condition in which high levels of blood glucose (sugar) caused by diabetes damage blood vessels in the retina. When damaged, these vessels become clogged or leak and are unable to deliver an adequate supply of nutrients to light-sensitive cells in the retina.

Like other types of retinopathy – a broad term that refers to diseases affecting the retina, usually because of abnormalities in these retinal blood vessels – diabetic retinopathy can cause partial or complete vision loss. It affects about half of the 14 million Americans with diabetes, and the primary reason why diabetics are four times more likely than the general population to suffer vision loss. Other forms of retinopathy, which occur less frequently, are caused by uncontrolled high blood pressure, premature birth or low birth-weight (and subsequent oxygen therapy) long-term intravenous drug abuse and other factors.

Anyone with Type 1 or Type 2 diabetes is at risk for diabetic retinopathy, the most common cause of vision loss in adults between ages 20 and 74. But the longer you have diabetes, the greater your risk. About one in five newly diagnosed Type 2 diabetics show signs of diabetic retinopathy; after 15 years with diabetes, that jumps to nearly 80 percent of Type 2 (and nearly all of those with Type 1).

Besides duration, certain groups of diabetics seem to be at greater risk of developing diabetic retinopathy:

• Men
• Pregnant women
• Those of African, Mexican and Native American descent
• Those who developed the diabetes early in life, or have high blood pressure and/or kidney damage.

In the early stages of diabetic retinopathy, tiny blood vessels in the retina become blocked or damaged, cutting off the food supply to small patches of light-sensing cells. Blood leaks into retinal tissue, causing swelling. At first, sight is rarely affected. This stage is called “background retinopathy.” Unless complications develop, treatment is rarely necessary for the disease in the early stage.

As the disease progresses, it enters an advanced or “proliferative stage” in which new, fragile blood vessels grow along the retina and in the clear, gel-like vitreous humor that fills the inside of the eye. Without timely treatment, these new blood vessels can bleed, cloud vision, and destroy the retina.

There are several complications that can occur in this proliferative stage:

• Macular edema occurs when the damaged blood vessels leak fluid and lipids onto the macula, the part of the retina that lets us see detail. The fluid makes the macula swell, blurring vision and making it hard to do tasks such as reading, watching television and driving. If not treated promptly, macular edema may cause permanent vision loss.
• Scar formation occurs as the body works to repair damage to the retina. Eventually, scar tissue can detach the retina from the back of the eye, causing permanent vision loss. If caught early, vision loss can be prevented or limited.
• Vitreous hemorrhage occurs when abnormal vessels bleed into the vitreous humor, blurring vision. Specks of blood may float through the field of vision. Large leaks, which often occur during sleep, can obscure sight, making it difficult to tell light from dark. The blood may clear on its own in a few days, but it may take months or even years. Type 1 diabetics are more likely to suffer total vision loss from large blood vessel hemorrhages.

Symptoms

Diabetic retinopathy often has no early warning signs. Once it advances, you may notice viusual changes such as:

• Blurred vision
• Sudden loss in vision in one or both eyes
• Changes in vision throughout the day
• Black spots
• Flashing lights
• Difficulty reading or seeing detailed work

Prevention

Better control of blood sugar levels can prevent or delay the complications of diabetic retinopathy. Research shows that people with insulin-dependent (Type 1) diabetes who tightly control their blood sugar levels have 76 percent less eye damage than those who don’t.

Some eyecare providers also advise the use of prescription supplements rich in specific vitamins and minerals to nourish the compromised retinal tissue and help prevent the onset or progression of diabetic retinopathy.

Treatment

To decrease the risk and progression of diabetic retinopathy, blood sugar and blood pressure must be tightly controlled in all diabetic patients. Two surgical treatments are effective in reducing vision loss — even people with advanced retinopathy have a 90 percent chance of keeping their vision when they undergo treatment before the retina is severely damaged. However, neither treatment is a cure.

• Laser surgery is done to seal leaky blood vessels, control swelling under the macula and inhibit the growth of new blood vessels. This procedure is performed in a doctor’s office or eye clinic and only takes a few minutes. After your pupils are dilated and drops are applied to numb the eye, you face the laser machine, and your doctor will hold a special lens to your eye. You may see green or red flashes of light, which may create a stinging sensation. For a day or two, you may experience blurry vision and eye soreness, which is controlled with medication.To control swelling under the retina’s central spot or macula, short bursts of laser are aimed directly at leaky blood vessels to vaporize or seal them – a procedure known as “focal laser therapy.” When the likelihood of blindness is high, “scatter laser therapy” is used to control the widespread growth of abnormal blood vessels; rather than hitting just one spot, the laser beam makes hundreds of tiny burns over the retina’s surface. Some peripheral or side vision is sacrificed to save the remaining vision.

  Laser surgery can also seal the retina to the back of the eye, preventing permanent vision loss from retinal detachment. Timely laser surgery can stabilize vision, but it cannot restore lost sight or repair a damaged retina. Laser surgery, however, can affect night vision and your ability to distinguish colors.

• Vitrectomy is a procedure in which the surgeon removes bloody vitreous from the eye and replaces it with a clear solution. Light can pass through this clear fluid, restoring normal sight. Since normal vitreous is mostly water, you won’t notice any difference between it and the clear fluid. Early vitrectomy is especially important for people with Type 1 diabetes, who are more likely to go blind as a result of large leaks (hemorrhaging).Depending on your health and eye structure, this procedure may be done in hospital under general anesthesia or in a doctor’s office under local anesthesia. The surgeon makes a small cut in the white of the eye. A special instrument sucks out the vitreous, then floods the eye with clear fluid. Afterward, an eye patch is worn for a few days or weeks. The eye will be red and feel sensitive, and eye drops are used to ward off infection.

Strabismus, also known as “crossed” or “misaligned” eyes, causes double vision.

Overview

Crossed eyes – medically known as strabismus (struh-BIZ-mus) – refer to a condition in which muscles that control eye movement are not properly coordinated or by problems with the nerves that control the eye muscles or with the brain where the signals for vision are processed. The result is one or both eyes turn inward, outward, upward or downward, or one or both eyes may move irregularly.

Also known as “misaligned eyes,” “wandering eyes” or “wall eyes,” strabismus can be constant or occur intermittently, which usually worsens when eye muscles are tired or during illness. When the eyes turn inward toward the nose (or crossed), the condition is called “esotropia” – the most common form. When they turn outward, it is called “exotropia.” When an eye turns upward it is known as “hypertropia” and “hypotropia” refers to an eye turned downward.

Strabismus is usually diagnosed during childhood and affects about 4 percent of children, afflicting boys and girls equally. But it can develop in older children or adults as the result of injury or diseases such as a brain disorder, diabetes, high blood pressure, multiple sclerosis or thyroid problems.

Most infants appear to be crossed-eyed, at least intermittently, during their first 3 months, as they are learning to focus. Most babies outgrow this. If your child’s eyes remain crossed or misaligned after 6 months, it may be infantile esotropia, a condition that often results from heredity or cerebral palsy. However, a condition often mistaken for strabismus is pseudostrabismus, in which a widened nasal bridge or extra fold of skin makes the white sclera appear less visible – giving the appearance that the eyes are crossed. This usually resolves as the infant grows and the facial structures change.

Symptoms

The obvious signs of strabismus are eyes that appear misaligned and don’t move together. Those with strabismus may experience:

• Double vision
• Difficulty focusing or judging distances
• Frequent blinking or squinting, especially in bright sunlight
• Tilting the head to look at things
• Frequent headaches
• Eye pain
• Nausea

Prevention

Strabismus cannot be prevented, but its complications can be avoided with early intervention. Even if you notice symptoms intermittently – when your child is ill, stressed or fatigued – alert your eyecare provider or pediatrician. Children should be monitored closely prior to entering school, especially if strabismus runs in your family. Most experts recommend an eye exam for all children before age 6 months, and then annually starting around age 3.

Treatment

Uncorrected strabismus represents one of the leading causes of vision loss and blindness in children. Generally, the younger children are when treated, the shorter the course of treatment and the higher the likelihood of success.

After infancy, children will not “outgrow” strabismus so the condition must be treated as soon as possible. When diagnosed early, correction is usually successful. But left uncorrected, strabismus can lead to amblyopia (lazy eye) and permanent loss of depth perception.

Before treatment is implemented, the precise cause should be determined. Crossed eyes can be indicative of other serious conditions such as diabetes, high blood pressure, and neurological disorders. Because there are many causes, treatment often involves a combination of elements including eyeglasses, vision therapy (orthoptics), surgery and medication.

• Eyeglasses help redirect the line of sight, improve focusing ability, relieve some of the symptoms, and encourage the eyes to straighten.
• Vision therapy, or orthoptics, train the eyes to work together, often with the use of an eye patch.
• Surgery is sometimes required to reposition the eye muscles and restore permanent control of the eyes. Frequently, repeat surgery must be performed to keep the eyes aligned. Vision therapy and corrective glasses may be prescribed before and after surgery.
• Drug therapy is controversial and usually considered a “last resort” treatment. Anticholinesterase miotics are eye drops or ointment that can enhance the focusing mechanisms of the eye. These are used on both children and adults, but have potential side effects such as including headaches, tearing, blurred or clouded vision, and decreased night vision. Botulinum toxin type A may offer an alternative to eye-muscle surgery, but this drug is rarely used on children, as it it injected into an eye muscle to paralyze it, allowing the opposing muscle to tighten and straighten the eye. The effects of the muscle paralysis wears off, but the eye may be permanently corrected. Side effects may include drooping of the eyelid, and loss of vertical eye movement.

Due to the high risk of recurrence and complications, children with strabismus must be closely monitored long term. Patching may continue throughout childhood.

If strabismus is not treated during childhood, the likelihood of correction is low. Treatment in pre-adolescents, adolescents and adults is possible but takes longer and is less effective. In adults, treatment may not improve eyesight at all. The condition may have progressed into lazy eye, a condition in which the nerves that transmit signals from the eye to the brain degenerate and cause permanent vision loss. Surgery to realign the muscles and straighten the eyes may be performed for cosmetic reasons only.

Improper positioning of wrists, elbows, shoulders, back, neck and eyes can cause discomfort.

Overview

Computer Vision Syndrome (CVS) refers to a group of vision-related problems and other symptoms that result from prolonged computer use. The American Optometric Association estimates that approximately 75 percent of regular computer users have CVS – as many as 60 million people, with about 1 million new cases each year.

Although CVS can result from using video games, multimedia entertainment devices, televisions or other electronic devices with a display monitor, visual symptoms ranging from eye strain and headaches to blurred vision and dry eye are more likely to occur from using a personal computer because of the letters on the screen. They are formed by tiny dots called pixels rather than a solid image and to keep these letters in focus, the eye must work harder.

Symptoms

Operating a computer for as little as 2-3 hours per day increases your risk of CVS symptoms, which include:

• Blurred near vision
• Difficulty in adjusting focus at different distances, such as near to far and back near again
• Eye strain, soreness or irritation
• Dry or red eyes
• Headaches, which typically disappear after periods of rest
• Irritation and discomfort while wearing contact lenses
• Soreness or discomfort in the neck, shoulders, back, forearms, wrists or hands

Besides strain, some of these symptoms result from ultraviolet radiation from the computer screen, which suppresses blinking. When blinking slows, lubrication from tears decreases and results in eye irritation, dryness, redness and other symptoms.

Prevention

Perhaps the easiest preventative measure is to take frequent breaks from continuous computer use – many experts recommend 10 minutes for each hour of use. You should also adjust your work station to minimize glare and maximize visual and physical comfort. This includes moving your chair, monitor and other items so the screen is at least 20 inches from your eyes, with its center about 6 inches below your eyes. The screen should be directly in front of you, not to the side or at an angle.

Meanwhile, to minimize the non-visual symptoms, hands and wrists should be about waist height while on the keyboard and forearms should be at a 90-degree angle to your body, parallel to the floor.

Eyewear plays a role in preventing and treating CVS. Make sure glasses and contact lenses are the correct prescription and designed for working at a computer. If you are presbyopic, “progressive” lenses can be tailor-made for computer users. Meanwhile, those who wear bifocals may find themselves keeping their head in an uncomfortable position, adding to problems.

When buying eyewear, ask about protective UV and anti-glare coatings to help to reduce these problems. You can also place filters with UV and glare protection on your monitor or investigate buying a flat “plasma” monitor, which doesn’t emit UV rays.

Treatment

Besides adjusting your work station and ensuring eyewear is suited for computer use, make a conscious effort to blink frequently and use artificial tears as recommended by your eyecare provider. One of the biggest complaints of patients with CVS is dry, irritated, red eyes – resulting from infrequent blinking and lower tear lubrication.

If you work under fluorescent lights, you may consider switching to incandescent bulbs. Some research indicates that fluorescent light can exacerbate eyestrain, headaches and other CVS symptoms; while they appear to be “on” constantly, fluorescents actually flicker about 60 times per second, which can fatigue the eye.

Overview

A chalazion (kuh-LAY-zee-on) is a cyst that forms in the eyelids as a result of a blockage in one or more of the meibomian glands that produce oil that forms the outer layer of tears. It initially may resemble a stye – being red, tender and swollen. But after a few days, chalazia typically become a painless, slow-growing bumps that, unlike a stye, do not contain live bacteria. However, they may attract bacteria and lead to an infection or occur as an after-effect of a stye. But in most cases, chalazia are gone within a few months, although one chalazion cyst may be followed by other, possibly larger cysts over several years.

Chalazia – named for the Greek word for small bump – can be so small that they are barely visible or as large as a pea. If they become large enough, they can press against the cornea, distorting the eyeball and blurring vision.

Symptoms

The first symptom is the swelling of the eyelid with little to no tenderness. Other symptoms include:

• A slow-growing bump that is firm and painless
• Surrounding skin may be loose
• Blurred vision if the chalazion is large

Prevention

If you are prone to chalazion, keeping the eyelid margins very clean and free of debris may prevent recurrences. Washing with a warm washcloth and very mild shampoo can do this. Scrub the outer eye and lashes gently and rinse with warm water at least once per day. It is also advised to keep your hands clean, to avoid rubbing your eyes and to not share eye makeup.

Treatment

Warm compresses are usually the first line of treatment, helping to unclog the duct and allowing pus to drain away. Simply place a folded washcloth moistened in warm water on the affected area for 10-15 minutes, four times a day. You can also gently massage the lid from the nose outward to help release blocked fluid from the gland.

Your eyecare practitioner may also prescribe eye drops, ointment or oral antibiotics, depending on the degree of inflammation and tenderness. Some research indicates that homeopathic medicines may dissolve the chalazion, but you should discuss this option with your eye doctor before starting the medicine. If the chalazion persists for more than 6 weeks, quick and easy surgery (chalazion excision) can be performed in a doctor’s office to remove it.

Overview

Color blindness, also known as color vision deficiency, is the inability to distinguish colors and shades or to recognize them at all. It occurs when the color-sensing cones of the retina are absent or do not function properly.

About 8 percent of males and 1 percent of females are color-blind to some degree. Most color-blind people have difficulty in distinguishing among various shades of the same color or seeing some colors as brightly as others; the inability to distinguish any colors at all and see the world in black-and-white is rare.

Most color blindness is inherited and present at birth. But acquired color blindness can result from cataracts, retinal or optical nerve disease, use of certain medications or simply the normal aging process — as we age, the normally clear lens begins to darken, making it harder to differentiate one dark color from another.

Normally, the pigments of each cone correspond to one of the primary colors of light – red, blue and green. In color blindness, there is a broad range of variances in these cones, including unbalanced proportions of cones for each color, absence of cones for one or more colors, and malfunction of cones for one or more colors. If no functioning cones are present, the rods take over in sensing lightness and darkness that enhance peripheral vision and vision in dim light.

Symptoms

While people with color blindness may have trouble distinguishing any or various colors or shades, the most common inherited form is “red/green” color blindness, in which there are problems seeing shades of red or green. For instance, red might appear as yellow or invisible or that pastel shades of yellow and green are indistinguishable. Another common form is blue/yellow color blindness.

Prevention

Color blindness is usually detected during a routine eye exam. Children should be tested for color blindness beginning at age 4. It cannot be prevented, but poses no threat to overall health. Although it may be inconvenience to some people, it presents no handicap on everyday life.

Treatment

While color blindness cannot be cured, there are many methods of coping with and compensating for the difficulties it presents, such as:

• Tinted contact lenses can make some colors appear dimmer or brighter, and may help some with certain color vision deficiencies. Some color-blind people claim that wearing a lens in one eye helps their vision and functioning, although there is no evidence indicating that the lenses actually allow them to see more colors. The lenses may blur vision and distort depth perception, creating potentially dangerous situations.

• Electronic Eyes are hand-held devices that identify colors. In such devices, color sensors activate an audio synthesizer that speaks the color aloud. The sensors, however, cannot read text.

If your child is color-blind, you can make modifications to help him/her identify colors. This includes activities such as labeling clothing, accessories and other items to help with coordination, and teaching how to recognize brightness and location of green, yellow and red positions on traffic lights and the meaning of signs by shape. You may also have to make adjustments in reading materials at school. Be on alert for books that use colored print and colored backgrounds and inform teachers that color-oriented and color-coded school assignments are not appropriate for your child.

Overview

A cataract is a clouding of the eye’s normally clear lens, leading to a progressive blurring or dimming of vision. It is the world’s leading cause of blindness and among the most common conditions related to aging – by age 65, you have a 50 percent chance of developing a cataract and by age 75, it jumps to 70 percent.

Cataracts can also result from injury, chronic eye diseases such as retinitis pigmentosa and ailments such as diabetes, or past use of corticosteroid medications or radiation treatments. Some researchers believe that lifestyle habits such as smoking and not wearing sunglasses to protect eyes against ultraviolet light are also risk factors.

A cataract occurs when proteins in the lens begin to clump together, forming a cloudy area. As these clumps grow, they interfere with vision by distorting or blocking the passage of light. Many cataracts begin to form in your 40s or 50s, but don’t affect vision until years later. Cataracts can occur in infants, usually the result of an infection during pregnancy such as toxoplasmosis, rubella, syphilis or herpes simplex. In children, a cataract can also result from metabolic disease.

There are three primary types:

• Nuclear cataracts are the most common, typically known as “age-related cataract.” Found in the center of the lens, they intefere with the ability to see distant objects. Interestingly, while the cataract is progressing, reading vision may temporarily improve because as the lens becomes more dense and cloudy, it changes the eye’s ability to focus, making it clearer up close than at far distances. This symptom is often referred to as “second sight.”

A nuclear cataract clouds the lens in the center.

• Cortical cataracts begin in the lens’s outer rim and grow “spokes” toward the central core. These spokes block light, causing glare and loss of contrast. Both near and distance vision are slowly disrupted. Diabetics often develop this type of cataract.

A cortical cataract develops spokes from the center of the lens outward.

• Subcapsular cataracts affect the back of your lens and usually progress more quickly than other types. Subcapsular cataracts cause blurriness and glare, and are more likely to strike those with diabetes, extreme nearsightedness, retinitus pigmentosa or people who take steroid medications.
  

  A subcapsular cataract builds up on the back of the lens.

Symptoms

A cataract starts out small and initially has little or no effect on vision. As the cataract grows and clouds more of the lens – what doctors call “ripens” – it will be harder to read and do other normal tasks. The word “cataract” means waterfall and for people with a ripe cataract, it is like trying to see through a waterfall or wall of fog. Other symptoms include:

• Blurred vision, as if you are looking through a cloudy piece of glass
• Double vision (diplopia)
• A sense that colors appear faded and decreased ability to distinguish some colors
• Seeing halos around lights
• Glare or sensitivity to light or from oncoming headlights while driving
• Difficulty seeing at night

Prevention

There is no way to prevent age-related cataracts, but several factors can increase your risk of developing them sooner, or developing other types of cataracts. If you have diabetes, you need to tightly control your blood sugar level. Women can reduce risk of congenital cataracts with rubella immunization before becoming pregnant and monitoring conditions such as herpes. Others factors that can play a role in prevention:

• Avoiding eye injuries, such as a blow or other trauma
• Not smoking
• Limiting or eliminating use of corticosteroids, major tranquilizers and diuretics
• Protecting eyes with quality sunglasses, especially if you live at a high altitude or spend a lot of time outdoors
• Avoiding alcohol abuse
• Eating a healthy diet. Although there is no definitive proof, some studies suggest that “antioxidant” nutrients such vitamin C may play a preventative role.

Treatment

In the early stages until the cataract ripens, your doctor may recommend stronger eyeglasses, using eye drops to widen the pupil and let in more light or adjusting lighting to reduce glare. When cataracts disrupt your daily life, it may be time for cataract-removal surgery, one of the most frequent procedures done in the U.S. If both eyes are affected, the surgeries are performed on different days.

More than 1.5 million Americans undergo surgery each year to remove the clouded lens, which is usually replaced with a clear, plastic intraocular lens (IOL). With an IOL, vision is restored to 20/40 or better in more than 90 percent of cases. You cannot see or feel the lens and it needs no special care. For those unable to wear an IOL, special glasses with powerful magnification or contact lenses are used.

Cataract surgery falls into two groups:

• Intracapsular: Both the lens and the protective capsule that surrounds it are removed. Once standard, this has been largely replaced by extracapsular surgery. Those who require intracapsular surgery may not be eligible for IOLs and instead need specially designed glasses or contacts.
• Extracapsular: Only the lens is removed. The front of the capsule is opened and ultrasonic waves break the lens into pieces (a process called “phacoemulsification”). The pieces are then vacuumed out of the capsule. The normal lens capsule surrounding the lens is left intact.