 |
|||||||||||
 |
|
 |
|||||||||
 |
|||||||||||
 |
||
 |
 |
 |
 |
||
In the following sections, we provide several documents that address frequently asked about eye conditions and diseases. These papers introduce you to very general information. AOA emphasizes that it is important to have your eyes examined regularly by your doctor of optometry. Click on the links below for a brief description and some answers to questions about the following eye conditions and diseases.
Myopia (nearsightedness)
Presbyopia
Spots and Floaters
20/20 VisionCrossed Eyes (strabismus)
Hyperopia (farsightedness)
Astigmatism
Color Deficiency
Glaucoma
Conjunctivitis
Macular Degeneration
Cataract
Dry Eye
Diabetic Retinopathy
Keratoconus
Blepharitis
Nearsightedness, or myopia, as it is medically termed, is a vision condition in which near objects are seen clearly, but distant objects do not come into proper focus. Nearsightedness occurs if your eyeball is too long or the cornea has too much curvature, so the light entering your eye is not focused correctly.
Nearsightedness is a very common vision condition that affects nearly 30 percent of the U.S. population. Some evidence supports the theory that nearsightedness is hereditary. There is also growing evidence that nearsightedness may be caused by the stress of too much close vision work. It normally first occurs in school age children. Since the eye continues to grow during childhood, nearsightedness generally develops before age 20.
A sign of nearsightedness is difficulty seeing distant objects like a movie or TV screen or chalkboard. A comprehensive optometric examination will include testing for nearsightedness. Your optometrist can prescribe eyeglasses or contact lenses to optically correct nearsightedness by altering the way the light images enter your eyes. You may only need to wear them for certain activities, like watching TV or a movie or driving a car, or they may need to be worn for all activities.
Refractive surgery or laser procedures are also possible treatments for nearsightedness as is orthokeratology. Orthokeratology is a non-invasive procedure that involves the wearing of a series of specially-designed rigid contact lenses to progressively reshape the curvature of the cornea over time.
Presbyopia is a vision condition in which the crystalline lens of your eye loses its flexibility, which makes it difficult for you to focus on close objects.
Presbyopia may seem to occur suddenly, but the actual loss of flexibility takes place over a number of years. Presbyopia usually becomes noticeable in the early to mid-forties. Presbyopia is a natural part of the aging process of the eye. It is not a disease and it cannot be prevented.
Some signs of presbyopia include the tendency to hold reading materials at arm's length, blurred vision at normal reading distance and eye fatigue along with headaches when doing close work. A comprehensive optometric examination will include testing for presbyopia.
To help you compensate for presbyopia, your optometrist can prescribe reading glasses, bifocals, trifocals or contact lenses. Since presbyopia can complicate other common vision conditions like nearsightedness, farsightedness and astigmatism, your optometrist will determine the specific lenses to allow you to see clearly and comfortably. You may only need to wear your glasses for close work like reading, but you may find that wearing them all the time is more convenient and beneficial for your vision needs.
Since the effects of presbyopia continue to change the ability of the crystalline lens to focus properly, periodic changes in your eyewear may be necessary to maintain clear and comfortable vision.
Spots (often called floaters) are small, semi-transparent or cloudy specks or particles within the vitreous, the clear, jelly-like fluid that fills the inside of your eyes. They appear as specks of various shapes and sizes, threadlike strands or cobwebs. Since they are within your eyes, they move as your eyes move and seem to dart away when you try to look at them directly.
Spots are often caused by small flecks of protein or other matter trapped during the formation of your eyes before birth. They can also result from deterioration of the vitreous fluid, due to aging; or from certain eye diseases or injuries. Most spots are not harmful and rarely limit vision. But, spots can be indications of more serious problems, and you should see your optometrist for a comprehensive examination when you notice sudden changes or see increases in them.
By looking in your eyes with special instruments, your optometrist can examine the health of your eyes and determine if what you are seeing is harmless or the symptoms of a more serious problem that requires treatment.
20/20 vision is a term used to express normal visual acuity (the clarity or sharpness of vision) measured at a distance of 20 feet. If you have 20/20 vision, you can see clearly at 20 feet what should normally be seen at that distance. If you have 20/100 vision, it means that you must be as close as 20 feet to see what a person with normal vision can see at 100 feet.
20/20 does not necessarily mean perfect vision. 20/20 vision only indicates the sharpness or clarity of vision at a distance. There are other important vision skills, including peripheral awareness or side vision, eye coordination, depth perception, focusing ability and color vision that contribute to your overall visual ability.
Some people can see well at a distance, but are unable to bring nearer objects into focus. This condition can be caused by hyperopia (farsightedness) or presbyopia (loss of focusing ability). Others can see items that are close, but cannot see those far away. This condition may be caused by myopia (nearsightedness).
A comprehensive eye examination by a doctor of optometry can diagnose those causes, if any, that are affecting your ability to see well. In most cases, your optometrist can prescribe glasses, contact lenses or a vision therapy program that will help improve your vision. If the reduced vision is due to an eye disease, the use of ocular medication or other treatment may be used.
Crossed-eyes (strabismus) occurs when one or both of your eyes turns in, out, up or down. Poor eye muscle control usually causes crossed-eyes. This misalignment often first appears before age 21 months but may develop as late as age six. This is one reason why the American Optometric Association recommends a comprehensive optometric examination before six months and again at age three.
There is a common misconception that a child will outgrow crossed-eyes. This is not true. In fact, the condition may get worse without treatment.
Treatment for crossed-eyes may include single vision or bifocal eyeglasses, prisms, vision therapy, and in some cases, surgery. Vision therapy helps align your eyes and solves the underlying cause of crossed-eyes by teaching your two eyes to work together. Surgery alone may straighten your eyes, but unless your eye muscle control is improved, your eyes may not remain straight. If detected and treated early, crossed-eyes can often be corrected with excellent results.
Farsightedness, or hyperopia, as it is medically termed, is a vision condition in which distant objects are usually seen clearly, but close ones do not come into proper focus. Farsightedness occurs if your eyeball is too short or the cornea has too little curvature, so light entering your eye is not focused correctly.
Common signs of farsightedness include difficulty in concentrating and maintaining a clear focus on near objects, eye strain, fatigue and/or headaches after close work, aching or burning eyes, irritability or nervousness after sustained concentration. Common vision screenings, often done in schools, are generally ineffective in detecting farsightedness. A comprehensive optometric examination will include testing for farsightedness.
In mild cases of farsightedness, your eyes may be able to compensate without corrective lenses. In other cases, your optometrist can prescribe eyeglasses or contact lenses to optically correct farsightedness by altering the way the light enters your eyes.
Astigmatism is a vision condition that occurs when the front surface of your eye, the cornea, is slightly irregular in shape. This irregular shape prevents light from focusing properly on the back of your eye, the retina. As a result, your vision may be blurred at all distances.
People with severe astigmatism will usually have blurred or distorted vision, while those with mild astigmatism may experience headaches, eye strain, fatigue or blurred vision at certain distances. Most people have some degree of astigmatism. A comprehensive optometric examination will include testing to diagnose astigmatism and determine the degree.
Almost all levels of astigmatism can be optically corrected with properly prescribed and fitted eyeglasses and/or contact lenses.
Corneal modification is also a treatment option for some patients.
Color vision deficiency means that your ability to distinguish some colors and shades is less than normal. It occurs when the color-sensitive cone cells in your eyes do not properly pick up or send the proper color signals to your brain. About eight percent of men and one percent of women are color deficient.
Red-green deficiency is by far the most common form and it results in the inability to distinguish certain shades of red and green. Those with a less common type have difficulty distinguishing blue and yellow. In very rare cases, color deficiency exists to an extent that no colors can be detected, only shades of black, white and grey.
Since many learning materials are color-coded, it is important to diagnose color vision deficiency early in life. This is why the American Optometric Association recommends a comprehensive optometric examination before a child begins school.
Color vision deficiency is usually inherited and cannot be cured, but those affected can often be taught to adapt to the inability to distinguish colors. In some cases, a special red tinted contact lens is used in one eye to aid persons with certain color deficiencies.
Glaucoma is an eye disease in which the internal pressure in your eyes increases enough to damage the nerve fibers in your optic nerve and cause vision loss. The increase in pressure happens when the passages that normally allow fluid in your eyes to drain become clogged or blocked. The reasons that the passages become blocked are not known.
Noticeable symptoms of glaucoma may be a gradual loss of side vision (above) or blurred vision (below).
Glaucoma is one of the leading causes of blindness in the U.S. It most often occurs in people over age 40. People with a family history of glaucoma, African Americans, and those who are very nearsighted or diabetic are at a higher risk of developing the disease.
The most common type of glaucoma develops gradually and painlessly, without symptoms. A rarer type occurs rapidly and its symptoms may include blurred vision, loss of side vision, seeing colored rings around lights and pain or redness in the eyes.
Glaucoma cannot be prevented, but if diagnosed and treated early, it can be controlled. Vision lost to glaucoma cannot be restored. That is why the American Optometric Association recommends annual eye examinations for people at risk for glaucoma (your doctor may, depending on your condition, recommend more frequent examinations). A comprehensive optometric examination will include a tonometry test to measure the pressure in your eyes; an examination of the inside of your eyes and optic nerves; and a visual field test to check for changes in central and side vision.
The treatment for glaucoma includes prescription eye drops and medicines to lower the pressure in your eyes. In some cases, laser treatment or surgery may be effective in reducing pressure.
Conjunctivitis is an inflammation of the conjunctiva, the thin, transparent layer that lines the inner eyelid and covers the white part of the eye.
The three main types of conjunctivitis are infectious, allergic and chemical. The infectious type, commonly called "pink eye" is caused by a contagious virus or bacteria. Your body's allergies to pollen, cosmetics, animals or fabrics often bring on allergic conjunctivitis. And, irritants like air pollution, noxious fumes and chlorine in swimming pools may produce the chemical form.
Common symptoms of conjunctivitis are red watery eyes, inflamed inner eyelids, blurred vision, a scratchy feeling in the eyes and, sometimes, a puslike or watery discharge. Conjunctivitis can sometimes develop into something that can harm vision so you should see your optometrist promptly for diagnosis and treatment.
A good way to treat allergic or chemical conjunctivitis is to avoid the cause. If that does not work, prescription or over-the-counter eye drops may relieve discomfort. Infectious conjunctivitis, caused by bacteria, can be treated with antibiotic eye drops. Other forms, caused by viruses, cannot be treated with antibiotics. They must be fought off by your body's immune system.
To control the spread of infectious conjunctivitis, you should keep your hands away from your eyes, thoroughly wash your hands before applying eye medications and do not share towels, washcloths, cosmetics or eye drops with others.
Macular degeneration is the leading cause of blindness in America. It results from changes to the macula, a portion of the retina that is responsible for clear, sharp vision and is located at the back of the eye.
As macular degeneration advances, a distorted, dark, or empty area often appears in the center of vision.
Most people with macular degeneration have the dry form, for which there is no known treatment. The less common wet form may respond to laser procedures, if diagnosed and treated early.
Some common symptoms are a gradual loss of ability to see objects clearly, distorted vision, a gradual loss of color vision and a dark or empty area appearing in the center of vision.
If you experience any of these, contact your doctor of optometry immediately for a comprehensive examination.
Central vision that is lost to macular degeneration cannot be restored. However, low vision devices such as telescopic and microscopic lenses can be prescribed to make the most out of remaining vision.
Recent research indicates certain vitamins and minerals may help prevent or slow the progression of macular degeneration. Ask your doctor of optometry about these. After age 60, an annual, comprehensive eye examination is an important to maintain eye health.
A cataract is a clouding of all or part of the normally clear lens within your eye, which results in blurred or distorted vision. Cataracts are most often found in persons over age 55, but they are also occasionally found in younger people.
No one knows exactly what causes cataracts, but it is known that a chemical change occurs within your eye to cause the lens to become cloudy. This may be due to advancing age, heredity or an injury or disease. Excessive exposure to ultraviolet radiation in sunlight, cigarette smoking or the use of certain medications are also risk factors for the development of cataracts.
Although cataracts develop without pain or discomfort, there are some indications that a cataract may be forming. These include blurred or hazy vision, the appearance of spots in front of the eyes, increased sensitivity to glare or the feeling of having a film over the eyes. A temporary improvement in near vision may also indicate formation of a cataract.
Currently, there is no proven method to prevent cataracts from forming. During a comprehensive eye examination, your optometrist can diagnose a cataract and monitor its development and prescribe changes in eyeglasses or contact lenses to maintain good vision.
If your cataract develops to the point that it affects your daily activities, your optometrist can refer you to an eye surgeon who may recommend surgery. During the surgery, the eye's natural lens is removed and usually replaced with a plastic artificial lens. After surgery, you can return to your optometrist for continuing care.
The tears your eyes produce are necessary for overall eye health and clear vision. Dry eye means that your eyes do not produce enough tears or that you produce tears which do not have the proper chemical composition. Often, dry eye is part of the natural aging process. It can also be caused by blinking or eyelid problems, medications like antihistamines, oral contraceptives and antidepressants, a dry climate, wind and dust, general health problems like arthritis or Sjogren's syndrome and chemical or thermal burns to your eyes.
If you have dry eye, your symptoms may include irritated, scratchy, dry, uncomfortable or red eyes, a burning sensation or feeling of something foreign in your eyes and blurred vision. Excessive dry eyes may damage eye tissue, scar your cornea (the front covering of your eyes) and impair vision and make contact lens wear difficult.
If you have symptoms of dry eye, see your optometrist for a comprehensive examination. Dry eye cannot be cured, but your optometrist can prescribe treatment so your eyes remain healthy and your vision is unaffected. Some treatments that your optometrist might prescribe include blinking more frequently, increasing humidity at home or work, using artificial tears and using a moisturizing ointment, especially at bedtime. In some cases, small plugs are inserted in the corner of the eyes to slow tear drainage. Sometimes, surgical closure of the drainage ducts may be recommended.
Diabetes is a disease that interferes with the body's ability to use and store sugar and can cause many health problems. One, called diabetic retinopathy, can weaken and cause changes in the small blood vessels that nourish your eye's retina, the delicate, light sensitive lining of the back of the eye. These blood vessels may begin to leak, swell or develop brush-like branches.
Blurred central or side vision (above, blurred side vision) or a blind spot in central vision (below) may indicate diabetic retinopathy.
The early stages of diabetic retinopathy may cause blurred vision, or they may produce no visual symptoms at all. As the disease progresses, you may notice a cloudiness of vision, blind spots or floaters.
If left untreated, diabetic retinopathy can cause blindness, which is one reason why it is important to have your eyes examined regularly by your doctor of optometry. This is especially true if you are a diabetic or if you have a family history of diabetes.
To detect diabetic retinopathy, your optometrist can look inside your eyes with an instrument called an ophthalmoscope that lights and magnifies the blood vessels in your eyes. If you have diabetic retinopathy, laser and other surgical treatments can be used to reduce its progression and decrease the risk of vision loss. Early treatment is important because once damage has occurred, the effects are usually permanent.
If you are a diabetic, you can help prevent diabetic retinopathy by taking your prescribed medication as instructed, sticking to your diet, exercising regularly, controlling high blood pressure and avoiding alcohol and smoking.
November is National Diabetes Month. Members of the American Optometric Association are joining with members of other health care organizations in an effort to prevent blindness in Americans with diabetes. If you or a member of your family has not received a dilated eye examination in the past year, you should contact your optometrist for an appointment. If you do not have an optometrist, call 1-800-262-3947 for the names of doctors in your area.
Keratoconus is a vision disorder that occurs when the normally round cornea (the front part of the eye) becomes thin and irregular (cone) shaped. This abnormal shape prevents the light entering the eye from being focused correctly on the retina and causes distortion of vision.
In its earliest stages, keratoconus causes slight blurring and distortion of vision and increased sensitivity to glare and light. These symptoms usually appear in the late teens or late twenties. Keratoconus may progress for 10-20 years and then slow in its progression. Each eye may be affected differently. As keratoconus progresses, the cornea bulges more and vision may become more distorted. In a small number of cases, the cornea will swell and cause a sudden and significant decrease in vision. The swelling occurs when the strain of the cornea's protruding cone-like shape causes a tiny crack to develop. The swelling may last for weeks or months as the crack heals and is gradually replaced by scar tissue. If this sudden swelling does occur, your doctor can prescribe eyedrops for temporary relief, but there are no medicines that can prevent the disorder from progressing.
Eyeglasses or soft contact lenses may be used to correct the mild nearsightedness and astigmatism that is caused by the early stages for keratoconus. As the disorder progresses and cornea continues to thin and change shape, rigid gas permeable contact lenses can be prescribed to correct vision adequately. In most cases, this is adequate. The contact lenses must be carefully fitted, and frequent checkups and lens changes may be needed to achieve and maintain good vision.
In a few cases, a corneal transplant is necessary. However, even after a corneal transplant, eyeglasses or contact lenses are often still needed to correct vision.
Blepharitis is a chronic or long term inflammation of the eyelids and eyelashes. It affects people of all ages. Among the most common causes of blepharitis are poor eyelid hygiene; excessive oil produced by the glands in the eyelid; a bacterial infection (often staphylococcal); or an allergic reaction.
Blepharitis is a chronic inflammation that affects the eyelids (1) and the eyelash hair follicles (2). Careful eyelid hygiene can do much to control blepharitis.
Seborrheic blepharitis is often associated with dandruff of the scalp or skin conditions like acne. It can appear as greasy flakes or scales around the base of the eyelashes and a mild redness of the eyelid. It may also result in a roughness of the normally smooth tissue that lines the inside of the eyelid.
Ulcerative blepharitis is less common, but more serious. It is characterized by matted, hard crusts around the eyelashes, which when removed, leave small sores that ooze or bleed. There may also be a loss of eyelashes, distortion of the front edges of the eyelids and chronic tearing. In severe cases, the cornea, the transparent front covering of the eyeball, may also become inflamed.
In many cases, good eyelid hygiene and a regular cleaning routine may control blepharitis. This includes frequent scalp and face washing; warm soaks of the eyelids; and eyelid scrubs. In cases where bacterial infection is a cause, eyelid hygiene may be combined with various antibiotics and other medications. Eyelid hygiene is especially important upon awakening because debris can build up during sleep.
If you experience symptoms of blepharitis, your doctor of optometry can determine the cause and recommend the right combination of treatments specifically for you.
Directions For A Warm Soak Of The Eyelids1. Wash your hands thoroughly.
2. Moisten a clean washcloth with warm water.
3. Close eyes and place washcloth on eyelids for about 5 minutes.
4. Repeat several times daily.Directions For An Eyelid Scrub
1. Wash your hands thoroughly.
2. Mix warm water and a small amount of shampoo that does not irritate the eye (baby shampoo) or use a commercially prepared lid scrub solution recommended by your optometrist.
3. Close one eye and using a clean wash cloth (a different one for each eye), rub the solution back and forth across the eyelashes and the edge of the eyelid.
4. Rinse with clear, cool water.
5. Repeat with the other eye.
All Rights Reserved, 2007