Pink eye affects the conjunctiva, the membrane lining the exposed surface of the eye and the inside surface of the eyelids, causing its namesake irritation.

Overview

Pink eye, medically known as conjunctivitis (kun-junk-te-VI-tis) is an infection or inflammation of the conjunctiva, the thin, protective membrane that covers the surface of the eyeball and inner surface of the eyelids. It is caused by bacteria, viruses and other germs that are transmitted to the eye through contaminated hands, towels, and eye makeup or extended wear contacts; by exposure to irritants such as chemicals, smoke or dust; or by pollen and other allergens. It is not uncommon for conjunctivitis eye to accompany a cold or flu.

Conjunctivitis is highly contagious -– and tends to be prevalent in daycare centers and schools -– spreading by direct person-to-person contact, in airborne droplets that are coughed or sneezed, or from sharing makeup, towels and washcloths. Its telltale sign is redness in the white of the eye that may be accompanied by increased tearing and/or a discharge that is watery or thick with mucus and pus and causes the eyelids to stick together.

Although usually a minor eye infection that improves within two weeks, some types can develop into serious corneal inflammation and vision loss if not treated quickly. If you wear contact lenses and suspect you have conjunctivitis, discontinue wearing your contacts until the condition clears; you may also need to replace your contact lenses to prevent recurrence.

There are four primary types:

• Bacterial conjunctivitis is the most common and serious type. It can affect one or both eyes and is usually accompanied by a heavy, yellow discharge. Caused by a variety of bacteria, including, staphylococci (staph) and streptococci (strep) and pneumococci, bacterial conjunctivitis is treated with antibiotic eye drops and typically resolves within 5 days. Children who are born to mothers with vaginal gonorrhea or chlamydia infections can develop conjunctivitis if contaminated secretions in the birth canal during vaginal delivery infect their eyes.Antibiotics are prescribed to help prevent the infection from spreading to the inner eye or other parts of the body, and impede infection to others. Warm compresses also help soothe the eye, and use of artificial tears will help clear discharges and dilute the bacterial toxins. Your eyecare provider may also recommend you scrub your eyelids with a solution made by adding 6 drops of tearless baby shampoo in 6 ounces of water.
• Viral conjunctivitis is usually caused by one adenoviruses, the family responsible for upper-respiratory illnesses such as colds, but can also result from herpes simplex, the rubeola virus that causes measles, Varicella-Zoster and other viruses. This type can also affect either one or both eyes, and usually causes a lighter discharge. Although viral conjunctivitis usually produces a superficial case that often clears on its own within two weeks, you should still see your eyecare provider to ensure it doesn’t lead to a more serious infection (keratoconjunctivitis) that can cloud the cornea.Antibiotics should not be used for this type — they are ineffective and, in fact, could be dangerous. Your eyecare provider may recommend a topical and oral anti-herpetic medication that can help suppress herpes viral infections. A warm compress, with or without diluted baby shampoo, may relieve some of the discomfort. Artificial tears or over-the-counter decongestant eye drops can also be used.
• Allergic conjunctivitis results from a response to airborne pollen, dust, smoke, or environmental agents. Both eyes are usually affected and may itch, tear excessively and discharge a stringy mucous. You may also have other allergic reactions, such as a runny or itchy nose. Allergy tests can identify specific causes, and repeated injections may desensitize you to the allergens.Topical eye drops are available to relieve symptoms, and depending on the severity, you eyecare provider or physician may also recommend oral medications such as over-the-counter or prescription decongestant-antihistamines. Eyecare products such as contact lens solutions or eye drops can cause allergic reactions as well. Discontinue use if you notice allergic conjunctivitis symptoms following the use of a particular product.
• Chemical conjunctivitis is caused by exposure to irritating liquids, powders, or fumes and requires immediate action. Common irritants in include chlorine, detergents, fuels, ammonia, smoke and pesticides. First, flush the eye with cold water continuously for 15 minutes. Then, apply an over-the-counter product such as Visine for minor irritants such as chlorine from a swimming pool; for chemicals such as ammonia or bleach, emergency medical treatment is needed.

Symptoms

The primary symptom is redness and inflammation in the white part of the eye. In addition, you may experience:

• Swelling, burning and/or itching in one or both eyes
• Excessive tearing or water
• An eye discharge that forms a crust, especially at night. In viral conjunctivitis, the discharge is usually thin and watery; in bacterial cases, it tends to be green or yellow and sticky.
• Blurred vision or sensitivity to light
• A gritty feeling in your eye

Prevention

The best way to prevent viral and bacterial conjunctivitis is to wash your hands frequently and avoid touching your eyes. It’s also advised to never share towels, washcloths or eye makeup. If you are pregnant, you should get tested for sexually transmitted diseases such as gonorrhea and chlamydia to avoid eye infections of your newborn (although as a preventative measure, they are treated with antibiotic eye drops following delivery).

To prevent allergic or chemical conjunctivitis, you need to be aware of possible irritants. Besides tests to can determine allergic triggers, take steps to avoid exposure to irritants by keeping your environment well-ventilated, particularly when using products that produce smoke, chemicals or fumes, and by wearing protective eyewear and clothing when handling chemicals.

Treatment

If you suspect conjunctivitis, see your eyecare provider. Often, a culture checking for bacterial growth is performed. If it is positive, you’ll be prescribed antibiotic eye drops or ointment and likely experience relief within a few days; cases of viral conjunctivitis may take a week or longer to heal, and your doctor may suggest over-the-counter eye drops, although many cases clear on their own. Allergic conjunctivitis tends to take longer unless exposure to the allergen is identified and eliminated.

Prior to applying eye drops, wipe pus off the eyelids with a cotton ball dipped in warm water. If you are giving drops to a child, gently pull the lower lid down and place one drop (or a 1/4 inch ribbon of ointment) into the small pouch that this forms. Avoid touching the dropper or tube to the eye.

In addition to medication, you can treat the symptoms with warm compresses to relieve itching and burning and help remove the discharge. Applying a clean washcloth to your eyelids for 10 to 20 minutes, several times a day. Your doctor may also suggest you gently scrub your eyelids with a solution made by adding 6 drops of tearless baby shampoo into 6 ounces of water. Avoid swimming until the condition has healed.

A nearsighted eye is “too long,” causing light to converge in front of the retina instead of on it, blurring distance vision.

Overview

Nearsightedness, medically known as myopia (my-OH-pee-uh), refers to vision that is good at close range but poor at a distance. Nearsightedness generally occurs because the eyeball is too “long” as measured from front to back – being oval-shaped instead of being spherical.

Because of the increased distance between the cornea and retina, light converges in front of the retina, rather than on it, making distant objects blurry. This may cause a nearsighted person to squint in order to see distant objects. Myopia comes from the Greek words myein, meaning shut, and ops, meaning eye.

Nearsightedness, also known as “shortsightedness” or “close-sightedness,” is the most common vision problem in the U.S., affecting between 25 and 40 percent of the population. It usually develops in children and teenagers during growth periods, and may require frequent changes in corrective lens prescriptions – a reason why regular eye exams are important. It usually stops progressing around age 20, when growth is completed, and may even decrease slightly through the rest of your life.

Most experts believe that nearsightedness is usually inherited, since it tends to run in families. Some believe that intense close-vision activities such as reading or computer use “stretches” the eye and may cause, and not only exacerbate, nearsightedness.

Symptoms

People who are nearsighted have blurred vision or difficulty focusing on “distance” objects such as road signs or a movie screen, but can clearly see “close” objects such as reading a newspaper or road map. Poor school performance is often the first clue in children, since they cannot see the blackboard. Other symptoms can include:

• Squinting to focus in the distance
• Eye strain
• Headaches can result from squinting or eye strain, especially when coupled with astigmatism.

Prevention

Most cases of nearsightedness are inherited, and therefore cannot be prevented. However, its severity may be affected by poor nutrition, stress and intense close visual work under poor lighting or too much glare. When performing close visual work, keep the work area well-lit and glare-free, and take breaks every 30 minutes or so from close visual activity, and focus on distant objects to give your eyes a break.

Treatment

Nearsightedness is diagnosed during a routine eye exam and usually described by a fraction number. For example, person with 20/100 vision can see at 20 feet what a person with perfect vision can see at 100 feet. Once diagnosed, your eyecare practitioner may review these treatments:

• Corrective lenses are the most popular and least invasive treatment for nearsightedness, but surgery can also be effective. If you are mildly nearsighted, your eyecare practitioner may suggest that you wear corrective lenses only for activities that require distance vision such as driving, watching a movie or participating in sports. For moderate or severe myopia, you may need corrective eyewear at all times. You will have several options:
  • Eyeglasses with concave lenses, which are thinner in the center and thicker on the edges to bend light so that it converges further back in the eye to reach the retina.
  • Contact Lenses. There are various options, including rigid gas-permeable (RGP) lenses, which may slow or even stop the progression of myopia because the cornea conforms to the shape of the lens. For this reason, RGP lenses are being used in a new, alternative treatment called orthokeratology in which a series of RGP lenses of varying strengths and thus, curvatures, are used to gradually reshape the cornea and place light on the retina.
• Acrylic corneal implants are small acrylic disks or rings that inserted just under the surface of the cornea to reshape the curvature and correct refraction. The implant is similar to a contact lens but eliminates the need for daily care. This is a new procedure in the United States. This procedure has several advantages over laser surgery, including the ability to change the implants multiple times, the possibility to reverse the procedure, and less modification to the cornea. The risks are similar to those of laser surgery. If side effects become pronounced, the implants may need to be removed.
• Surgery has been effective for many people with nearsightedness, but its long-term effects are still being studied. Surgery also carries the risk of side effects, including increased sensitivity to glare, seeing halos around lights, poor vision, dry eye and others. In general, surgery for nearsightedness is not recommended for those under age 18. Among the options:
  • LASIK(laser in situ keratomileusis) is a procedure in which a surgeon slices a flap into the cornea and a laser removes some corneal tissue from beneath the sliced area. This helps “flatten” the cornea to improve distance vision.
  • Radial keratotomy(RK) is a procedure in which tiny cuts are made into the periphery of the cornea after the eye is anesthetized, causing the central portion of the cornea to flatten.
  • Photorefractive keratotomy (PRK) uses a laser beam to remove tissue from the outer surface of the cornea, reshaping it to improve its focus.

In macular degeneration, damage to the macula (the central spot on the retina) causes diminished central vision.

Overview

Macular degeneration (MAK-yu-lar DEE-gen-or-a-shon) is a chronic, progressive disease that gradually destroys sharp central vision. It affects up to 10 million Americans and is so commonly associated with aging that it is also known as “age-related macular degeneration,” or AMD.

The leading cause of vision loss in those older than age 50, AMD occurs due to a deterioration of the macula, a tiny spot in the central portion of your retina comprised of millions of light-sensing cells that help produce central or “straight-ahead” vision.

As you age, these light-sensitive photoreceptors in the macula – the Latin word for “spot” – become thin, worn or damaged and covered with tiny hyaline deposits known as drusen. This can cause objects directly in front of you to appear blurry and lack in detail; AMD doesn’t affect peripheral (side) vision. There may be a fuzzy “hole” in vision. For instance, when looking at a face, an AMD patient may only see the ears clearly or when viewing a frame picture, the frame may be in focus but not the artwork itself.

There are two types of AMD:

• Dry macular degeneration occurs because of a thinning in the tissues in the macula and a dysfunction in the light-sensitive cells. This initially produces subtle vision loss, such as a fuzzy appearance of objects and eventually blank spots over the eye’s central vision. Dry AMD causes about 90 percent of cases.
• Wet macular degeneration is characterized by the development of abnormal blood vessels in the area between your retina and a layer of supporting tissues behind it, called choroid tissue. As these blood vessels leak fluid, they damage retinal cells. Over the course of days or weeks, scar tissue forms, creating a blind spot in the center of your vision. Although wet AMD occurs in only about 10 percent of cases, it’s responsible for nearly 90 percent of severe vision loss from this disease.

What causes these changes is unclear, but age and heredity appear to be the main culprits, although gender and race appear to play a role. Women are more likely than men to get AMD and it affects about one in nine Caucasians between ages 65 to 74 and approximately one in four older than age 75 but is uncommon in Asians, African-Americans, Americans Indians and other groups. Researchers also suspect these other risk factors:

• Long-term exposure to light, especially ultraviolet light and blue light (the wavelength just above ultraviolet)
• Low blood levels of minerals and antioxidant vitamins, such as A, C and E
• Cigarette smoking
• Heart disease, high cholesterol and other circulatory problems
• A diet rich in partially hydrogenated fats, such as those found in margarine and many snack foods

Symptoms

AMD usually develops gradually and painlessly. Symptoms of the disease tend to vary, depending on the type of macular degeneration you develop.

In dry AMD, you may notice:

• A gradual haziness in vision
• A “grayness” in vision and colors appearing to be more dim
• A blind spot in the center of your visual field
• Printed words becoming increasingly blurry
• In advanced cases, faces and printed words may become hard to recognize

In wet AMD, you may notice:

• Visual distortions, such as straight lines appearing wavy
• Sudden, decreased central vision

Prevention

Although you cannot change your genetic makeup or stop Father Time, there are steps you can take that may increase your chances of preventing AMD or keep it from advancing:

• Eat healthfully. A diet rich in fruits, vegetables and other foods containing antioxidant vitamins A, C and E is believed to help prevent AMD. Good sources of these nutrients include deep green, yellow and orange produce such as cabbage, broccoli, chard, spinach, squash, cantaloupe, mango and sweet potatoes. Some researchers also suspect that food containing lutein and zeaxanthin — found in high concentrations in egg yolks, corn and spinach — may be beneficial. Many experts recommend at least five pieces or servings of produce each day. And some research suggests that zinc-rich foods such as oysters, fish and legumes may also offer a protective effect.
• Consider vitamin supplements. In addition to eating well to help prevent AMD, those diagnosed with the disease may lower their risk of advanced AMD by taking vitamin supplements. In a study published in the October 2001 issue of Archives of Ophthalmology, researchers found that that people at high risk of developing advanced stages of AMD lowered their risk by about 25 percent when they consumed a daily supplement rich in vitamins C and E, beta-carotene and zinc.The specific dosages used in the study included 500 milligrams of vitamin C, 400 international units of vitamin E, 15 milligrams of beta-carotene, 80 milligrams of zinc as zinc oxide and 2 milligrams of copper as cupric oxide. (Copper was added to prevent copper deficiency, which may be associated with high levels of zinc supplementation.) These dosages exceed the RDA and what is in most multi-vitamin formulas sold over-the-counter, so consult with your doctor before starting this or any vitamin therapy.
• Wear sunglasses when outdoors to help block out harmful ultraviolet rays. Orange, yellow, or amber-tinted lenses can filter out both ultraviolet and blue light that may damage your retina.
• Quit smoking. Smokers are two to three times more likely to develop AMD compared to non-smokers.
• Drink wine. A 1998 study found that people who drank wine in moderation were less likely to develop AMD. Although this finding needs additional study, and many experts don’ty advise you start drinking wine if you don’t already, other research has found that drinking one glass of wine each day offers a protective effect against heart disease, which is also a risk factor for AMD.
• Get regular eye exams. Early detection of macular degeneration is the key to preventing serious vision loss. If you’re older than age 50, eye exams generally are recommended every year – especially if you have a family history of AMD. Eye exams are also important because a simple vision test using an Amsler grid — a chart with a grid of straight lines that may appear wavy, blurred or dark if you have a vision problem — can detect early changes in your vision that may otherwise be difficult to detect.If your doctor suspects wet macular degeneration, you may undergo a procedure known as fluorescein angiography to detect leaky blood vessels under your retina. In this procedure, fluorescent dye is injected into a vein in your arm and photographs are taken as the dye passes through blood vessels in the back of your retina and choroid to detect abnormalities in these blood vessels and the surrounding tissue.

Treatment

Photodynamic therapy is sometimes used to treat some forms of macular degeneration. This procedure combines a cold laser and intravenously injecting a light-sensitizing dye that concentrates in the newly growing blood vessels under the macula. When the dye is hit by light from the laser, it releases substances that close off the blood vessels without damaging the retina.

Some people with wet AMD can be treated with:

• Macular translocation surgery, a new treatment in which a fold in the wall of the eyeball is created to move the central part of the macula from leaking blood vessels. To qualify for this procedure, you must have recent vision loss and healthy tissue in that portion of the macula.
• Thermal laser surgery, which is sometimes used in early stages to seal off blood vessels that have developed under your macula. However, the results are often disappointing and only 20 percent of AMD patients are candidates for this procedure.

In most cases, it’s not possible to reverse damage caused by AMD. But there are ways to cope with the disease and make the most of the sight you have. Using magnifiers and large-print books can help you read, and you can purchase large-face clocks and telephones; bright light may also help. AMD patients are advised to avoid driving at night or in heavy traffic and to remove hazards in their home, such as throw rugs and other tripping hazards.

Overview

Low vision is a term used to describe having impaired but some useful vision that that cannot be fully corrected by conventional eyewear, surgery or medical treatments. More than 13 million Americans have some degree of low vision — often a loss in visual sharpness or acuity. However, low vision may also include a loss in the general field of vision, increased light sensitivity, distorted vision, a loss in contrast or other impairments that affect the quality of life and the ability to do everyday activities.

People with low vision are not blind, although many are classified as being “legally blind” — a term used to describe visual acuity no better than 20/200 in the better eye with visual correction such as eyeglasses or contact lenses. This means that they must be 20 feet away to clearly see an object that a person with 20/20 eyesight can see clearly from 200 feet away. “Partially sighted” is the other general classification associated with low vision and refers to a visual acuity between 20/70 and 20/200 in the better eye with the best-corrected lens in place.

Low vision often occurs from complications of eye diseases such as diabetic retinopathy, macular degeneration, retinitis pigmentosa inoperable cataracts, retinal lesions or glaucoma. It can also result from stroke, eye or head injuries, brain tumors, birth defects or even the natural aging process. Although low vision cannot be cured, there are various devices and adaptive products to help you live a more productive and safe life. Many of these devices — along along with counseling and other rehabilitative therapies — are specifically prescribed on a case-by-case basis by an eyecare provider.

Symptoms

Any difficulties in seeing — whether it’s recognizing a familiar face, trouble reading or seeing objects such as furniture or walls — could be symptoms of low vision. Other symptoms include:

• Blurred or distorted vision
• Central or multiple field loss, in which a dark hole, patches or hazy area appears in the center or around objects
• The loss of peripheral vision, in which objects in the center of vision appear clear but those on the sides are blurry
• Light sensitivity or glare
• A loss in contrast, in which objects blend in with their surroundings

Prevention

Since low vision often results from eye and other diseases, prevention may occur by quick management of those conditions.

Treatment

A thorough eye exam by your eyecare providers that includes a comprehensive health history is necessary to determine the possible cause of your low vision, and help determine which specific optical and non-optical devices may be most useful to you.

Optical devices include but are not limited to:

• Magnifiers that can be held or mounted onto eyeglasses or on a special headband that help for reading, writing, sewing, and other “close” activities.
• Spectacle-mounted telescopes that are useful for seeing longer distances, such as across the room to watch television.
• Closed-circuit television (also called CCTVs) that enlarge reading material on a video screen. Some are portable, while some can be connected to a computer. The user can adjust the image brightness, size, contrast and background illumination.

Non-optical devices include products such as large-print reading material, check-writing guides, enlarged telephone dials, high contrast watch faces, self-threading needles, “talking” computers, clocks and other products, and special lighting to reduce glare.

In addition to products, your eyecare provider may recommend resources that provide social services to those with low vision, counseling to deal with emotional effects, or occupational therapists that come to your home to help you make it safer and more efficient.

Overview

Lazy eye, medically known as amblyopia (am-blee-OH-pee-a), is the loss or lack of development of vision, usually in one eye. It affects about 2 percent of children and is rare among adults. In most cases, the abilities of one eye are limited so it does not develop properly. The brain gives preference to the dominant eye. If left untreated, the brain will eventually “ignore” images from the weaker eye, and eventually its nerve connections degenerate.

This degenerative process usually begins with an inherited condition and appears during infancy or early childhood. Lazy eye needs to be diagnosed between birth and early school age (age 8 or 9), since it is during this period that brain “chooses” its visual pathway and may ignore the weaker eye permanently. Even with early treatment, ongoing complications and recurrence are possible.

There are several underlying causes, including:

• Crossed eyes (strabismus). This causes double vision (diplopia) when children use both eyes at the same time. One image may appear clearer than the other, and the brain will block out the weaker image when double vision is prolonged.
• Focus inequality, in which one eye is much more nearsighted, farsighted or astigmatic than the other. Again, the brain gives preference to the stronger eye.
• Structural problems in the eye or eyelid, such as a cataract or ptosis (a drooping eyelid).

Symptoms

Lazy eye is not always easy to recognize, since a child with worse vision in one eye does not necessarily have lazy eye. This is why all children – including those with no symptoms – should get a complete eye examination by age 3, and sooner if there is a family history of any eye condition or disease or if you detect any of these symptoms:

• The ability to see well on only one side, or clearly seeing some but not all objects clearly
• Trouble judging depth or distance
• Covering one eye to see, or tilting the head to read or perform other activities
• Frequent rubbing or winking
• Bumping into objects on the side of the weaker eye or other signs of clumsiness
• Infants may cry if one eye is covered

Prevention

To prevent permanent loss of vision in a “weak” eye, newborns should receive an eye exam to rule out congenital abnormalities. Visual acuity testing should begin by age 3, and be done at least annually thereafter. If the results of a screening exam suggest that your child has lazy eye, you will be referred to an ophthalmologist for further testing and assessment.

Treatment

Treatment is usually successful with prompt intervention and treatment. There are three goals: correcting the underlying problems, strengthening the weaker eye and producing a clear visual image in both eyes. To achieve this, your eyecare practitioner may employ:

• Eyeglasses with prism, concave, convex or bifocal lenses to strengthen and restore focus to the weaker eye, encouraging the brain to use it over time. Eyeglasses can also be used to treat focus inequality caused by conditions such as nearsightedness or farsightedness.
• Contact lenses are also used in cases of severe refractive inequality (between the two eyes), or a single contact lens may be prescribed for the amblyopic eye.

   

• Monitored patching consists of covering the stronger eye for defined periods – usually for at least 6 months – to strengthen the muscles that control the weaker eye. Once the child’s vision is restored, occasional patching may still be needed for several years. As an alternative, some doctors use an opaque contact lens or prescribe atropine eye drops to temporarily blur vision in the stronger eye.
• Vision therapy, or orthoptics, can strengthen, coordinate and improve the functions of both eyes, especially in the early years of life.
• Surgery can “reposition” eye muscles to restore permanent control of the weaker eye. If cataracts are the cause of the amblyopia, they must be surgically removed. After cataract removal, an artificial lens can restore focus, and eventually restore strength to the weaker eye. Other surgical procedures may also be beneficial when other eye diseases are the cause.

In keratoconus, the cornea progressively thins, causing vision distortion.

Overview

Keratoconus (kehr-a-toh-KOH-nus) is a non-inflammatory condition in which the center of the cornea progressively thins and develops a cone-shaped bulge that blurs and distorts vision. A normal cornea is round, with even curvature like that of a sphere. But with keratoconus, the curvature is irregular and too steep, like the narrow end of an egg. Any change in the shape of the cornea changes the way light passes through the eye, and results in a change in vision. When the cornea is too steep, light converges in front of the retina, causing nearsightedness.

Keratoconus, which comes from the Greek words karato meaning “cornea” and konos meaning “cone,” usually begins during the late teen years or early 20s and can progress over a 10- to 20-year span. Each eye can be affected differently, but as the cornea bulges more, distortion and nearsightedness increases. Rarely, keratoconus causes sudden swelling in the cornea that leads to rapid changes in vision.

A definitive cause of keratoconus is unknown, but several theories exist. Some eyecare specialists and researchers believe the condition is hereditary, since it appears to run in families. Others believe it is degenerative. Another theory is that it may be related to the endocrine system, since keratoconus develops after puberty, while other research suggests that it may be related to other conditions, since it seems to occur in conjunction with diseases such as Marfan’s syndrome, Down syndrome, mitral valve prolapse and retinitus pigmentosa.

One theory vigorously being investigated is that keratoconus may be the result of frequent eye-rubbing. Some research indicates that at least two in three keratocones have reported a history of vigorously rubbing their eyes with their knuckles. But itchiness can be caused by the changes in the corneal tissue, so it is unclear whether the eye rubbing is a cause or effect of the condition. Whether a cause or effect, eye-rubbing is known to worsen the condition and patients with keratoconus are advised to avoid rubbing their eyes.

Symptoms

The most noticeable symptom is blurred vision – especially at distances – or distorted images like that of astigmatism. Other symptoms you may notice include:

• Sensitivity to light or glare
• Excessive tearing
• Seeing halos around streetlights or other objects, especially at night
• “Double” vision or seeing multiple images of a single object
• Increased squinting to see images clearly
• A frequent change in corrective lens prescription (i.e. at every annual eye exam)

Prevention

Since the exact cause of keratoconus is unknown, definitive ways to prevent the condition cannot be recommended. However, it is generally recognized that eye rubbing exasperates the condition in those with it.

Treatment

Keratoconus is diagnosed with special instruments and microscopes that enable eyecare providers to detect evidence of cornea thinning. One indication is Fleischer’s ring, a brownish circular deposit at the base of the abnormal zone of the cornea. Others include Vogt’s striae, which are fine, white lines deep within the middle layer of the cornea, and swelling, cracks or scars on the cornea. To help diagnose and track the progress of keratoconus, the exact shape of the cornea can be mapped over time using keratometry or computerized corneal topography.

Once diagnosed, there are several treatment options:

• Corrective lenses. Eyeglasses or soft contact lenses are typically used to correct the mild nearsightedness and astigmatism that is caused in the early stages of keratoconus. As the disorder progresses and the cornea continues to thin and change shape, rigid gas permeable (RGP) are usually prescribed to more adequately correct vision. When wearing RPG lenses, tears under the lenses smooth out the cornea’s irregular shape. However, proper fit is essential, so you may require frequent checkups and lens changes to maintain good vision. Poor fitting lenses may aggravate keratoconus, rendering the lenses uncomfortable and even scarring the cornea.
• Corneal transplants are used in more severe cases. In this procedure, the cone-shaped cornea is removed and replaced with a donated cornea. The success rate is 90 percent, much higher than that of other organ transplants because the cornea does not contain or require blood. After the operation, almost all patients still require glasses or contacts to further correct their nearsightedness.
• Corneal grafting, medically known as epikeratophakia, consists of an eye surgeon grafting a layer of corneal epithelial (surface or skin-like) cells from the patient’s own cornea in the upper layer around the central cone to build up and flatten the slope of the cornea. The success rate compares to that of corneal transplants, but it offers the advantage of not requiring donated tissue.

Keratitis (KEHR-ah-TI-tis) is an inflammation or irritation of the cornea, often characterized by a cloudiness or loss of luster in this transparent membrane covering the iris and pupil. There are many types, causes and degrees of severity of keratitis. Generally, the infection occurs after the cornea has been injured or penetrated, allowing bacteria or fungi to enter and the deeper the infection, the more severe its symptoms and complications.

Keratitis affects about 50,000 Americans each year, most of them recurring cases. It is usually easy to treat – typically with antiviral or antibiotic eye drops – but prompt treatment is important; untreated cases can cause permanent eye damage and help give keratitis the dubious distinction of being the most common cause of infection-caused corneal blindness in the U.S.

Among the most common types is herpes simplex keratitis, caused by the same herpes simplex virus that causes cold sores. This infection usually begins with an inflammation of the conjunctiva, the membrane lining the eyelid, and the portion of the eyeball that comes into contact with it. Subsequent infections, called “dendritic keratitis,” are characterized by a pattern of lesions that resemble the veins of a leaf. Those who have been diagnosed with the herpes simplex virus need to be vigilant, since when untreated, this form of keratitis can be serious – leading to vision loss, corneal scarring, chronic inflammation and glaucoma. Herpes-caused recurrences are common, and can be triggered by stress, fatigue or even exposure to outdoor activities such as boating and skiing, in which sunlight reflects off of the surfaces such as water and snow.

Other viruses that cause keratitis include the varicella zoster virus (also a herpes virus), which is associated with chickenpox and shingles, and the adenoviruses, which cause upper respiratory infections.

Bacterial keratitis is caused by bacteria, often resulting from improper care and cleaning of contact lenses or wearing soft daily-wear lenses overnight (which increases risk about 10-fold, according to some research). Contaminated eye makeup can also cause bacterial keratitis. This type of infection is usually aggressive, characterized by waking up with your eyelids stuck together.

Other forms of keratitis result from vitamin A deficiency, poor hygeine, a reaction to antibiotics medications, or rheumatic diseases such as rheumatoid arthritis and Sjögren’s Syndrome, in which eye dryness can lead to a greater susceptability toward corneal irritation and injury.

Symptoms

The number and severity of symptoms may vary, but typically you may experience:

• Pain
• Blurred vision or reduced clarity
• Eye redness, itching or watering
• A feeling as if something was in your eye
• Eye discharge
• Sensitivity to light

Prevention

Many cases of keratitis could be avoided with common sense and good hygiene. Protecting your cornea from cuts with sports and protective eyewear is the first step, since keratitis also results from a corneal injury. If you have a cold sore or genital herpes, avoid touching your eyes – and avoid over-the-counter steroid eyedrops, which can worsen this type of infection. If you have daily-wear contact lenses, remove them nightly and follow the cleaning recommendations by the manufacturer. Also avoid sharing eye makeup.

If you’re prone to dry eye or have a rheumatic condition, keep eyes “hydrated” with moisturizing eye drops recommended by your eyecare provider. Also consume a well-balanced diet, including vitamin A-rich foods such as carrots, squash, mangoes, sweet potatoes and other orange-colored produce; organ meats such as beef or lamb liver; and spinach.

Treatment

Prompt treatment by your eyecare provider is important to determine the specific type of keratitis – and its most effective treatment. You will be asked questions about your symptoms, your lifestyle, and your overall health. A history of cold sores, chickenpox, shingles or arthritis are important in the evaluation. Your doctor will then examine the surface of the cornea, looking for a tiny ulcer or other abnormalities.

Antiviral eyedrops are typically used to treat symptoms in cases caused by the herpes simplex type 1 and other viruses, but these cases can recur because the virus may remain in your body. In severe cases, your doctor may scrape off disease tissue after applying anesthetic eyedrops. After wearing an eyepatch, you may have to wear a special contact lens to prevent re-infection.

Oral or eyedrop antibiotics are used for other infections, and if you wear contact lenses, you may be advised to replace your lenses. For cases caused by dry eye, artificial tears for lubrication are usually effective. Vitamin supplementation is given in cases where a vitamin A deficiency is the suspected cause.

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.