Eye Conditions A-Z
Accommodative infacility is an inability to quickly adjust focus when looking from near to far, far to near, or both. It is often noticed when looking up after a long period of reading or computer work and finding it difficult to focus on objects across the room. Eye strain, copying problems and headaches are other symptoms. Some researchers feel this condition, if untreated, can lead to the development of nearsightedness. Treatment consists of vision therapy followed by reading glasses to reduce visual stress.
Age-Related Macular Degeneration (ARMD)
Age-related macular degeneration is the leading cause of blindness in the US. It is a disease that affects the macula, the central area of the retina responsible for fine, detailed vision (i.e. reading, driving, recognizing faces, watching TV). As we age, the macula thins and deposits called drusen are formed. There are three types of ARMD:
• Dry (or atrophic): a slow, degenerative process with gradual vision loss over many years.
• Wet: sudden onset with symptoms that include blurry vision or straight lines appearing distorted.
Amblyopia, commonly referred to as “lazy eye” is reduced vision in one or both eyes. Amblyopia is not a common vision disorder; it affects less than 5% of the population. Amblyopia is caused by an abnormality that interferes with the normal process of seeing. This interference can occur at the level of the eye, in the connections between the eye and the brain or in the brain itself. The presence of strabismus, or a wandering eye, can also cause amblyopia because the brain “turns off” the deviated eye in order to avoid seeing double. Amblyopia can also be caused by trauma to the eye or head, and diseases that affect the eye, such as cataracts. Vision problems such as nearsightedness, farsightedness, or astigmatism, if uncorrected, can cause amblyopia.
Except in cases where there is an obvious eye turn or other abnormality, amblyopia can go undetected because of the absence of symptoms, especially when there is one normal seeing eye. A thorough exam by an eye care professional is the only way to determine if amblyopia is present. Detected early enough, most amblyopia can be successfully eliminated.
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.
Blepharitis, often referred to as “granulated eyelids” because of their appearance, is simply an inflammation of the outer edges of the eyelids where the eyelashes originate (the eyelid margins). It is a common condition that may never totally go away, but it can be controlled by treatment. Blepharitis can be caused by a number of infectious organisms, though in most cases it is related to seborrhea, a common condition of the skin and hair known as “dandruff.” It is not caused by a need for glasses, although if you do need glasses and tend to rub your eyes, this could add to the likelihood of lid infections. Blepharitis itself does not affect your eyesight but it can make the eyes look bloodshot. The edges of the eyelids may stay red much of the time, making it look as if you have been crying.
A variety of procedures are used in treating blepharitis. Lid compresses or scrubs consist of a warm, clean wash cloth placed on the eyelashes for several minutes followed by gently scrubbing the debris from the eyes. Most people with dandruff-related blepharitis benefit from treating their scalp at the same time. A mild baby shampoo can be used on the eyelashes for chronic blepharitis, with the approval of your eye care provider. If your blepharitis is severe, you may be given a 1 to 2 week course of treatment with an antibiotic medication (either drop or oral).
A normally clear lens in the eye that becomes cloudy is called a cataract. As the lens becomes cloudy, vision becomes blurred and/or distorted. Eyeglasses or contact lenses can be prescribed to provide clear vision until cataracts develop to the point where they impair vision. Then they need to be surgically removed. During this surgery, an intraocular lens implant is usually inserted to replace your natural lens. However, contact lenses or eyeglasses are also often needed to fully restore vision.
(see Color Vision Deficiencies)
Color Vision Deficiencies
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 8% of men and 1% 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.
The following color vision tests are available at the University Eye Center:
• Farnsworth Lantern
• Farnsworth-Munsel 100 Hue Test
• Ishihara Test
• Pseudo-Isochromatic Plates (PIP)
• Standard and desaturated D-15 color test
• Vivid Red-Green
Conjunctivitis (“Pink Eye”)
Acute conjunctivitis, commonly known as “pink eye,” is an inflammation of the mucous membrane on the inside of the eyelid and upper eyeball. There are three main types of conjunctivitis:
• Infectious (caused by a virus or bacteria): Viral conjunctivitis is usually accompanied by a sore throat and is highly contagious among children, often spread by hand-to-eye contact.
• Allergic: This form of conjunctivitis is most common in spring and fall, but can occur anytime when and if one is allergic to pets, cosmetics, most dust or any other allergens.
• Chemical: Chemical conjunctivitis can be caused by irritants like air pollution, noxious fumes and chlorine in swimming pools.
• Less frequent causes include irritation from wind, dust, or overexposure to sunlight.
Symptoms include discomfort, discharge, red watery eyes, swelling, itching, blurred vision and light sensitivity.
If bacterial conjunctivitis is suspected, treatment generally consists of antibiotic drops and ointments. In cases of allergic or chemical conjunctivitis, try to avoid the irritant that is causing the condition. Viral conjunctivitis will not respond to antibiotics, and must be fought off by your body’s immune system. Prescription or over-the-counter eye drops may be recommended to relieve discomfort for any type of conjunctivitis.
• Keep your hands away from your eyes;
• Thoroughly wash hands before and after applying eye medications;
• Do not share towels, washcloths, cosmetics, or eye drops;
• Promptly seek treatment.
If untreated, conjunctivitis can sometimes develop into a condition that can harm vision, so be sure to see your optometrist promptly for diagnosis and treatment.
The cornea is the clear covering of the front of the eye which bends (or refracts) light rays as they enter the eye.
Diabetic retinopathy occurs when there is a weakening or swelling of the tiny blood vessels in the retina of your eye, resulting in blood leakage, the growth of new blood vessels and other changes. If diabetic retinopathy is left untreated, blindness can result. Several factors that increase the risk of developing retinopathy include smoking, high blood pressure, drinking alcohol and pregnancy.
Dry Eye Syndrome
Dry eye syndrome occurs when your tear glands don’t produce enough tears or do not produce good quality tears. It often occurs in people who are healthy and it is more common with older people because as you age, your eyes produce fewer tears.
If dry eye is untreated, it can harm your eyes. Excessive dry eye can damage tissue and possibly scar the cornea of your eye, impairing vision. Dry eye can make contact lens wear more difficult due to increased irritation and a greater chance of eye infection. Common treatments range from over-the-counter lubricant (moisture) drops to prescription medications. To keep dry eye symptoms in check, see your eye care provider as directed.
Esophoria is a muscle imbalance of the eyes, so the eyes have a tendency to cross or “over converge.” When esophoria is considerable, it is difficult to hold the eyes in a straight, forward position. Because the eyes are pulling in, the effort required to keep them looking straight ahead will lead to eyestrain. This is especially true when tasks are at arm’s length. Depending on the individual’s ability to cope with the esophoria, initial symptoms of red eyes, burning, frontal headaches, intermittent blurred vision or possibly double vision may occur.
Reading and writing is also affected. A common cause of esophoria is nearsightedness. Other causes include near vision focus problems and poor visual hygiene (lighting, posture, reading distance). It is treated in a similar matter as compared to exophoria.
The optometrist treats esophoria in several ways, depending on the specific cause. Prescription lenses, bifocals, reading glasses, special prism glasses and/or vision therapy may be prescribed to eliminate or ease the severity of muscle imbalance. In each case, special tests are performed to determine the amount and cause of the esophoria so that appropriate therapy can be utilized. Improved visual hygiene is very important.
Exophoria is a muscle imbalance of the eyes, so that the eyes have a tendency to “pull out” or diverge. It is the most common muscle imbalance of the eyes. In small degrees, this condition is considered normal. With normal amounts of exophoria your visual system can keep the eyes aligned without excessive eyestrain or fatigue. With larger amounts of exophoria the effort needed to keep the eyes aligned may be great enough to cause symptoms of eyestrain. These symptoms are most noticeable with near visual tasks such as reading or computer work.
Symptoms of exophoria are usually associated with reading or computer work and can include sore or tired eyes, headaches, lack of concentration, occasional double vision and avoidance. When these symptoms occur at near because of excessive exophoria the condition is called convergence insufficiency.
Exophoria can be treated through the use of lenses, prisms and/or vision therapy (eye exercises). How it is treated, or whether it needs to be, is dependent on the amount and the causes of the muscle imbalance. Exophoria is the most common functional vision problem and the prognosis with vision therapy is excellent for all ages.
Extreme myopia is a term applied to amounts of myopia greater than 7 diopters. Myopia of this degree can cause degenerative changes in the eye.
The retina that covers the back of the eyes is a light sensitive nervous tissue. This means that in addition to regular vision, if the retina is pulled, torn, tugged on or deprived of oxygen it will respond by sending an impulse to the brain that appears to you as a flash of light. This is why getting poked or hit in the eye often results in “seeing stars.” Migraine headaches are sometimes preceded by the appearance of lights that appear as jagged lines or heat waves and may last up to 10 or 20 minutes. It is possible to notice these without the headache in which case it is termed an ophthalmic migraine.
Since flashes can be indicators of traction or pulling forces on the retina they should be taken seriously and evaluated promptly. In most cases there may be no serious problem, but the more serious causes of flashes, if undetected and untreated can result in loss of vision. Call your eye care provider immediately if you notice sudden onset of flashes in your vision.
(see Spots and Floaters)
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 or if the tissues that produce fluid in the eyes are secreting too much fluid. The reasons for these changes are not known. For more information, visit our section on glaucoma and ocular hypertension.
Headache is one of the most frequent reasons patients seek an eye examination. When headaches are caused by the eyes, they tend to be related to use of the eyes and can be relieved by resting them. Headaches that regularly follow prolonged reading or other close work, working at a computer screen or watching television or a movie are probably eye related.
Headaches related to the eyes are usually:
• Felt somewhere around the eyes or above the forehead
• Not one sided or felt in the back of your head near the neck
• Not severe enough to require strong painkillers or to wake you up at night
• Not accompanied by nausea, vomiting or flashes of light
Uncorrected astigmatism or farsightedness can cause an eye strain type of headache and signify a need for glasses. Eye muscles that are not working together properly can result in eye “pulling” or forehead headaches. Some eye diseases and conditions cause a sensation of actual eye-ache, the same you might have in coming out of a dark theater into the bright sunlight. An eye-ache in only one eye, especially, should be brought to the attention of your eye doctor.
Other causes of headaches are tension, poor posture, sinus trouble, high blood pressure or a spasm of the blood vessels such as in a migraine.
Very rarely, headaches turn out to have a serious cause, such as a brain tumor, but these are almost always accompanied by other symptoms. If no eye-related reason can be found for your headaches, your eye care provider may advise you to consult your family doctor or an internist, neurologist or otolaryngologist.
Hyperopia, or farsightedness, 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 vision screenings, often done in schools, are generally ineffective in detecting farsightedness. A comprehensive optometric examination will include testing for farsightedness.
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.
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 the farsightedness.
Iritis is an inflammation of the iris, the colored part of the eye. It can occur in one eye or, less commonly, in both. Iritis is a serious condition, so do not treat it casually or ignore it, hoping it will go away by itself. Although there are many possible causes, most of the time the exact reason cannot be identified. Iritis can occur independently or in association with inflammations elsewhere in the body, such as in the joints (arthritis or spine spondylitis), teeth or sinuses or bowels (colitis). Usually, it is not due to an infection, is not contagious and is not related to infectious “pink eye.”
If iritis is not treated promptly, there can be complications that threaten vision. These complications occur because the inflamed iris gets “sticky” and adheres to the lens, which lies directly behind it, or to the cornea, which is in front of it. The areas of stickiness, called synechiae, are dangerous because they may block the normal channels for fluid flow within the eye and lead to secondary glaucoma, a serious condition that can lead to blindness. Other complications of iritis are cataract, retinal swelling and other internal eye damage.
Iritis may cause no symptoms at all. Or, an eye with iritis may look “bloodshot” and may be extremely uncomfortable in bright light, sunlight or the glare of car headlights. Pain or aching in the eye or brow can occur from the tightening of inflamed muscles as they constrict the pupil in bright light. There may also be some blurring of vision.
If the iritis is severe, the intraocular muscles must be rested with cycloplegic (or dilating) eye drops. These help relieve much of the pain because they allow the iris to rest by preventing their normal constriction, especially in bright light. The dilation also keeps the iris away from the lens and cornea so that synechiae are less likely to form and, if already present, pull free those that are not firmly attached. Even though cycloplegic drops blur your vision, which can be annoying and make it difficult to see well enough to read or even drive a car, they are very important and should not be discontinued until you have been told by your eye care provider that it is safe to do so.
Other treatments include steroid eye drops or oral anti-inflammatory agents. Medications may produce very rapid relief at first, but the complete control of an iritis attack tends to be a slow process. As the inflammation subsides, you will be given instructions for reducing the medications gradually. Stopping treatment suddenly can result in a flare-up of the attack.
An iritis attack may be completely cleared by treatment and may never occur again. However, once you have had iritis, a red eye even years later, could indicate another attack. If at any time you think an attack may be starting, see your eye care provider right away. Be sure to tell the doctor who is treating you for any type of eye problem that you have a history of iritis.
Keratoconus is a degenerative disease which produces steepening and thinning of the central cornea resulting in a cone-shaped deformity. It typically begins in the early 20s and commonly progresses slowly over several years. Usually, vision can be corrected during the early stages with spectacles, and later on, vision can be improved with the use of contact lenses which provide a smooth corneal surface.
Low vision refers to vision that cannot be corrected to normal levels (20/20) even with the use of glasses or contact lenses. Anyone with non-correctable low (reduced) vision is visually impaired, and can have a wide range of problems.
The World Health Organization uses the following classifications of visual impairment. When the vision in the better eye with the best possible glasses correction is:
•20/30 to 20/60 is considered mild vision loss, or near-normal vision
•20/70 to 20/160 is considered moderate visual impairment, or moderate low vision
•20/200 to 20/400 is considered severe visual impairment, or severe low vision
•20/500 to 20/1,000 is considered profound visual impairment, or profound low vision
•less than 20/1,000 is considered near-total visual impairment, or near total blindness
•No Light Perception is considered total visual impairment, or total blindness
Low vision affects people at school, on the job, and at home. It can make daily activities, like reading, writing, watching television and walking, very difficult.
People with low vision may experience:
• Blurred Vision: Objects appear out of focus. Causes include macular degeneration, diabetes, corneal disease and/or cataracts.
• Central Field Loss: A dark or hazy patch appears in the center of objects. Causes include macular degeneration and optic atrophy.
• Contrast Loss and Glare Problems: Objects blend with background; lights are distracting or uncomfortable. Causes include glaucoma, cataracts, corneal disease and albinism.
• Multiple Field Loss: Dark patches are scattered around objects. Causes include diabetes, glaucoma, retinal detachment and trauma.
• Distortion: Objects appear out of shape, crooked, deformed, wavy or doubled. Causes include macular degeneration, diabetes and retinal detachment.
• Tunnel Vision: Objects in the center of the field of vision are visible; objects on the sides are missing. Causes include glaucoma, retinitis pigmentosa and stroke.
Myopia, or nearsightedness, 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% 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-aged 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 eye care provider can prescribe eyeglasses or contact lenses to optically correct nearsightedness. 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.
Ocular hypertension can occur in people of all ages, but it occurs more frequently in African Americans, those over age 40 and those with family histories of ocular hypertension and/or glaucoma. It is also more common in those who are very nearsighted or who have diabetes. People with ocular hypertension have higher than normal eye pressures, but the eyes show no adverse effect.
Oculomotor dysfunction is a fairly common eye problem in which people are unable to follow a moving object accurately with their eyes (pursuit fixation) or are unable to quickly shift their eyes from one object to another (saccadic fixation). Oculomotor dysfunction develops over a period of time, but can be treated by following a course of corrective eye exercises. For more information, visit our section on Vision Therapy.
Pediatric aphakia is a term that is reserved for those patients who had a cataract removed in infancy. To obtain proper vision, we fit special soft contact lenses enabling the connection between the eye and the brain to develop normally.
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 eye care provider can prescribe reading glasses, multifocal or progressive eyeglass lenses or contact lenses. Since presbyopia can complicate other common vision conditions like nearsightedness, farsightedness and astigmatism, your eye care provider will determine the specific lenses to allow you to see clearly and comfortably.
Refractive errors include:
See those specific sections for more information.
Retinal detachment is a serious condition that can lead to severe visual impairment or even total blindness in the affected eye. If any part of the retina is lifted or pulled from its normal position, it is considered detached, and will cause some vision loss. Retinal detachment can occur at any age, but it is more common in mid-life and later. It affects men more than women, and caucasians more than African Americans. It is more likely to occur in people who are extremely nearsighted. Heredity may also play a part since it tends to run in families.
The retina normally lies smoothly and firmly against the inside back wall of the eyeball and functions much like the film in the back of a camera. Any tiny tears or holes in the retina can allow fluid to seep under the retina, separating it from the back wall of the eye.
Most of the eye’s interior is filled with vitreous, a gel-like substance that helps maintain its round shape. The vitreous contains millions of fine fibers that are normally attached to the retina and may at some point be pulled free. Once in a while, this pulling results in one or more tears or tiny holes in the retina. Then, the fluid from the vitreous compartment of the eye can leak through the hole(s) and get under the retina. Retinal tears may also result from a hard blow or injury to the eye, though this is rare.
Because the retina is such a sensitive part of the visual system, anything that disturbs it will cause visual symptoms. When it tears, you are likely to have a sudden appearance of floaters - a shower of “cobwebs” in your field of vision - which may be accompanied by “flashes,” a sensation of seeing a flashing bright light. Though it is normal to have a few floaters, a sudden increase in their number and size is a warning sign that a detachment may have occurred. The flashes are sensations from the retina as it is pulled or torn.
Depending on the severity of the retinal detachment or hole, one, or a combination of procedures may be required. These include laser surgery, cryotherapy, scleral buckle, drainage, vitreous surgery or intraocular gas injection. Once a retinal detachment has occurred, however, all holes and tears that have allowed fluid to collect under the retina must be sealed.
Retinopathy is change or damage to the retinal tissue caused by systemic disease, trauma or congenital conditions. The most common diseases that cause retinopathy are diabetes and high blood pressure.
Spots and Floaters
One of the most common visual complaints is the appearance of spots (also called floaters) in front of the eyes. They often appear as specks of various shapes and sizes, threadlike strands or cobwebs. They tend to move as your eyes move and seem to dart away when you try to look directly at them. They may be most noticeable while reading or working on a computer or looking at well-lit background.
Spots are most often caused by small flecks of protein or other matter trapped in the vitreous (the gel-like substance that fills the back cavity of the eye) during the development of the eyes before birth. They can also result from deterioration of the vitreous gel as it ages or from certain eye diseases or injuries. These small spots tend to be less optically clear than the surrounding vitreous. In the proper lighting, they can cause a shadow to fall on the retina. You see the shadow as a spot. Since it is inside your eye, the spot will move whenever you move your eye to try to focus on it.
In most cases, spots are not harmful and rarely limit vision. But in some instances spots can be indications of more serious problems. To tell the difference between normal spots and serious ones you should see your eye care provider for a comprehensive examination when you first notice them or if you notice sudden changes in the size or quantity of spots.
Strabismus, or crossed-eyes, occurs when one or both eyes turn in or out, up or down, or may wander in several directions. Poor eye muscle control usually causes crossed-eyes. With strabismus, the eye-brain connection is not working properly. The signals traveling between the eyes and the brain can get mixed up or confused. Since the two eyes point in different directions, each eye sends a different picture to the brain causing confusing visual signals. As a result, the brain will eventually ignore or suppress messages from one eye in order to make sense of what is seen.
An eye turn may be present all the time or may only appear when a person is tired, ill or concentrating intensely. The brain reacts as if one eye is closed. Strabismus can be caused by trauma, fever, infection, stroke, brain tumor or uncorrected refractive errors such as hyperopia or myopia. Because suppression cannot be felt, a person may be unaware that this is happening. Some causes are not only sight-threatening but can be life-threatening. If you suspect an eye turn, consult your eye care provider immediately.
Symptoms of strabismus include:
• Wandering eye
• Person turns his or her face to one side
• Tilting head to one side
• Avoiding eye contact
• Bumping into things
• Closing one eye in bright sunlight
• Covering one eye while reading
Strabismus can be treated with eyeglasses, prisms, vision therapy and in some cases, surgery. Any person suspected of having a strabismus should receive a thorough eye examination by an eye care professional to determine the best course of treatment.