Conditions We Treat

A cataract is a clouding of the normally clear lens of your eye. For people who have cataracts, seeing through cloudy lenses is a bit like looking through a frosty or fogged-up window. Clouded vision caused by cataracts can make it more difficult to read, drive a car (especially at night) or see the expression on a friend's face.

Most cataracts develop slowly and don't disturb your eyesight early on. But with time, cataracts will eventually interfere with your vision.

At first, stronger lighting and eyeglasses can help you deal with cataracts. But if impaired vision interferes with your usual activities, you might need cataract surgery. Fortunately, cataract surgery is generally a safe, effective procedure.

Symptoms

Signs and symptoms of cataracts include:

• Clouded, blurred or dim vision
• Increasing difficulty with vision at night
• Sensitivity to light and glare
• Need for brighter light for reading and other activities
• Seeing "halos" around lights
• Frequent changes in eyeglass or contact lens prescription
• Fading or yellowing of colors
• Double vision in a single eye

At first, the cloudiness in your vision caused by a cataract may affect only a small part of the eye's lens and you may be unaware of any vision loss. As the cataract grows larger, it clouds more of your lens and distorts the light passing through the lens. This may lead to more noticeable symptoms.

When to see a doctor

Make an appointment for an eye exam if you notice any changes in your vision. If you develop sudden vision changes, such as double vision or flashes of light, sudden eye pain, or sudden headache, see your doctor right away.

Causes

Most cataracts develop when aging or injury changes the tissue that makes up your eye's lens.

Some inherited genetic disorders that cause other health problems can increase your risk of cataracts. Cataracts can also be caused by other eye conditions, past eye surgery or medical conditions such as diabetes. Long-term use of steroid medications, too, can cause cataracts to develop.

How a cataract forms

The lens, where cataracts form, is positioned behind the colored part of your eye (iris). The lens focuses light that passes into your eye, producing clear, sharp images on the retina — the light-sensitive membrane in the eye that functions like the film in a camera.

As you age, the lenses in your eyes become less flexible, less transparent and thicker. Age-related and other medical conditions cause tissues within the lens to break down and clump together, clouding small areas within the lens.

As the cataract continues to develop, the clouding becomes denser and involves a bigger part of the lens. A cataract scatters and blocks the light as it passes through the lens, preventing a sharply defined image from reaching your retina. As a result, your vision becomes blurred.

Cataracts generally develop in both eyes, but not evenly. The cataract in one eye may be more advanced than the other, causing a difference in vision between eyes.

Types of cataracts

Cataract types include:

• Cataracts affecting the center of the lens (nuclear cataracts). A nuclear cataract may at first cause more nearsightedness or even a temporary improvement in your reading vision. But with time, the lens gradually turns more densely yellow and further clouds your vision.
  As the cataract slowly progresses, the lens may even turn brown. Advanced yellowing or browning of the lens can lead to difficulty distinguishing between shades of color.
• Cataracts that affect the edges of the lens (cortical cataracts). A cortical cataract begins as whitish, wedge-shaped opacities or streaks on the outer edge of the lens cortex. As it slowly progresses, the streaks extend to the center and interfere with light passing through the center of the lens.
• Cataracts that affect the back of the lens (posterior subcapsular cataracts). A posterior subcapsular cataract starts as a small, opaque area that usually forms near the back of the lens, right in the path of light. A posterior subcapsular cataract often interferes with your reading vision, reduces your vision in bright light, and causes glare or halos around lights at night. These types of cataracts tend to progress faster than other types do.
• Cataracts you're born with (congenital cataracts). Some people are born with cataracts or develop them during childhood. These cataracts may be genetic, or associated with an intrauterine infection or trauma.
  These cataracts also may be due to certain conditions, such as myotonic dystrophy, galactosemia, neurofibromatosis type 2 or rubella. Congenital cataracts don't always affect vision, but if they do they're usually removed soon after detection.

Risk factors

Factors that increase your risk of cataracts include:

• Increasing age
• Diabetes
• Excessive exposure to sunlight
• Smoking
• Obesity
• High blood pressure
• Previous eye injury or inflammation
• Previous eye surgery
• Prolonged use of corticosteroid medications
• Drinking excessive amounts of alcohol

Prevention

No studies have proved how to prevent cataracts or slow the progression of cataracts. But doctors think several strategies may be helpful, including:

• Have regular eye examinations. Eye examinations can help detect cataracts and other eye problems at their earliest stages. Ask your doctor how often you should have an eye examination.
• Quit smoking. Ask your doctor for suggestions about how to stop smoking. Medications, counseling and other strategies are available to help you.
• Manage other health problems. Follow your treatment plan if you have diabetes or other medical conditions that can increase your risk of cataracts.
• Choose a healthy diet that includes plenty of fruits and vegetables. Adding a variety of colorful fruits and vegetables to your diet ensures that you're getting many vitamins and nutrients. Fruits and vegetables have many antioxidants, which help maintain the health of your eyes.
  Studies haven't proved that antioxidants in pill form can prevent cataracts. But, a large population study recently showed that a healthy diet rich in vitamins and minerals was associated with a reduced risk of developing cataracts. Fruits and vegetables have many proven health benefits and are a safe way to increase the amount of minerals and vitamins in your diet.
• Wear sunglasses. Ultraviolet light from the sun may contribute to the development of cataracts. Wear sunglasses that block ultraviolet B (UVB) rays when you're outdoors.
• Reduce alcohol use. Excessive alcohol use can increase the risk of cataracts.

Read about diagnosis and treatment.

Dry eyes is a common condition that occurs when your tears aren't able to provide adequate lubrication for your eyes. Tears can be inadequate for many reasons. For example, dry eyes may occur if you don't produce enough tears or if you produce poor-quality tears.

Dry eyes feel uncomfortable. If you have dry eyes, your eyes may sting or burn. You may experience dry eyes in certain situations, such as on an airplane, in an air-conditioned room, while riding a bike or after looking at a computer screen for a few hours.

Treatments for dry eyes may make you more comfortable. These treatments can include lifestyle changes and eyedrops. You'll likely need to take these measures indefinitely to control the symptoms of dry eyes.

Symptoms

Signs and symptoms, which usually affect both eyes, may include:

• A stinging, burning or scratchy sensation in your eyes
• Stringy mucus in or around your eyes
• Sensitivity to light
• Eye redness
• A sensation of having something in your eyes
• Difficulty wearing contact lenses
• Difficulty with nighttime driving
• Watery eyes, which is the body's response to the irritation of dry eyes
• Blurred vision or eye fatigue

When to see a doctor

See your doctor if you've had prolonged signs and symptoms of dry eyes, including red, irritated, tired or painful eyes. Your doctor can take steps to determine what's bothering your eyes or refer you to a specialist.

Causes

Tear glands and tear ducts Tear glands and tear ducts Dry eyes are caused by a lack of adequate tears. Your tears are a complex mixture of water, fatty oils and mucus. This mixture helps make the surface of your eyes smooth and clear, and it helps protect your eyes from infection.

For some people, the cause of dry eyes is decreased tear production. For others it's increased tear evaporation and an imbalance in the makeup of your tears.

Decreased tear production

Dry eyes can occur when you're unable to produce enough tears. The medical term for this condition is keratoconjunctivitis sicca(ker-uh-toe-kun-junk-tih-VY-tis SIK-uh). Common causes of decreased tear production include:

• Aging
• Certain medical conditions, including diabetes, rheumatoid arthritis, lupus, scleroderma, Sjogren's syndrome, thyroid disorders and vitamin A deficiency
• Certain medications, including antihistamines, decongestants, hormone replacement therapy, antidepressants, and drugs for high blood pressure, acne, birth control and Parkinson's disease
• Laser eye surgery, though symptoms of dry eyes related to this procedure are usually temporary
• Tear gland damage from inflammation or radiation

Increased tear evaporation

Common causes of increased tear evaporation include:

• Wind, smoke or dry air
• Blinking less often, which tends to occur when you're concentrating, for example, while reading, driving or working at a computer
• Eyelid problems, such as out-turning of the lids (ectropion) and in-turning of the lids (entropion)

Imbalance in tear composition

The tear film has three basic layers: oil, water and mucus. Problems with any of these layers can cause dry eyes. For example, the oil film produced by small glands on the edge of your eyelids (meibomian glands) might become clogged. Blocked meibomian glands are more common in people with inflammation along the edge of their eyelids (blepharitis), rosacea or other skin disorders.

Risk factors

Factors that make it more likely that you'll experience dry eyes include:

• Being older than 50. Tear production tends to diminish as you get older. Dry eyes are common in people over 50.
• Being a woman. A lack of tears is more common in women, especially if they experience hormonal changes due to pregnancy, using birth control pills or menopause.
• Eating a diet that is low in vitamin A, which is found in liver, carrots and broccoli, or low in omega-3 fatty acids, which are found in fish, walnuts and vegetable oils
• Wearing contact lenses

Complications

People who have dry eyes may experience these complications:

• Eye infections. Your tears protect the surface of your eyes from infection. Without adequate tears, you may have an increased risk of eye infection.
• Damage to the surface of your eyes. If left untreated, severe dry eyes may lead to eye inflammation, abrasion of the corneal surface, corneal ulcer and vision problems.
• Decreased quality of life. Dry eyes can make it difficult to perform everyday activities, such as reading.

Prevention

If you experience dry eyes, pay attention to the situations that are most likely to cause your symptoms. Then find ways to avoid those situations in order to prevent your dry eyes symptoms. For instance:

• Avoid air blowing in your eyes. Don't direct hair dryers, car heaters, air conditioners or fans toward your eyes.
• Add moisture to the air. In winter, a humidifier can add moisture to dry indoor air.
• Consider wearing wraparound sunglasses or other protective eyewear. Safety shields can be added to the tops and sides of eyeglasses to block wind and dry air. Ask about shields where you buy your eyeglasses.
• Take eye breaks during long tasks. If you're reading or doing another task that requires visual concentration, take periodic eye breaks. Close your eyes for a few minutes. Or blink repeatedly for a few seconds to help spread your tears evenly over your eyes.
• Be aware of your environment. The air at high altitudes, in desert areas and in airplanes can be extremely dry. When spending time in such an environment, it may be helpful to frequently close your eyes for a few minutes at a time to minimize evaporation of your tears.
• Position your computer screen below eye level. If your computer screen is above eye level, you'll open your eyes wider to view the screen. Position your computer screen below eye level so that you won't open your eyes as wide. This may help slow the evaporation of your tears between eye blinks.
• Stop smoking and avoid smoke. If you smoke, ask your doctor for help devising a quit-smoking strategy that's most likely to work for you. If you don't smoke, stay away from people who do. Smoke can worsen dry eyes symptoms.
• Use artificial tears regularly. If you have chronic dry eyes, use eyedrops even when your eyes feel fine to keep them well-lubricated.

Learn about diagnosis and treatment.

Dry macular degeneration is a common eye disorder among people over 65. It causes blurred or reduced central vision, due to thinning of the macula (MAK-u-luh). The macula is the part of the retina responsible for clear vision in your direct line of sight.

Dry macular degeneration may first develop in one eye and then affect both. Over time your vision worsens, which may affect your ability to do things such as read, drive and recognize faces. But this doesn't mean you'll lose all of your sight.

Early detection and self-care measures may delay vision loss due to dry macular degeneration.

Symptoms

Dry macular degeneration symptoms usually develop gradually and without pain. They may include:

• Visual distortions, such as straight lines seeming bent
• Reduced central vision in one or both eyes
• The need for brighter light when reading or doing close work
• Increased difficulty adapting to low light levels, such as when entering a dimly lit restaurant
• Increased blurriness of printed words
• Decreased intensity or brightness of colors
• Difficulty recognizing faces

Dry macular degeneration usually affects both eyes. If only one eye is affected, you may not notice any changes in your vision because your good eye may compensate for the weak eye. And the condition doesn't affect side (peripheral) vision, so it rarely causes total blindness.

Dry macular degeneration is one of two types of age-related macular degeneration. It can progress to wet (neovascular) macular degeneration, which is characterized by blood vessels that grow under the retina and leak. The dry type is more common, but it usually progresses slowly (over years). The wet type is more likely to cause a relatively sudden change in vision resulting in serious vision loss.

When to see a doctor

See your eye doctor if:

• You notice changes in your central vision
• Your ability to see colors and fine detail becomes impaired These changes may be the first indication of macular degeneration, particularly if you're over age 50.

Causes

Parts of the inner eye Inner eye No one knows exactly what causes dry macular degeneration. But research indicates it may be related to a combination of heredity and environmental factors, including smoking and diet.

The condition develops as the eye ages. Dry macular degeneration affects the macula — an area of the retina that's responsible for clear vision in your direct line of sight. Over time tissue in your macula may thin and break down.

Risk factors

Factors that may increase your risk of macular degeneration include:

• Age. This disease is most common in people over 65.
• Family history and genetics. This disease has a hereditary component. Researchers have identified several genes that are related to developing the condition.
• Race. Macular degeneration is more common in whites than it is in other people.
• Smoking. Smoking cigarettes or being regularly exposed to smoke significantly increases your risk of macular degeneration.
• Obesity. Research indicates that being obese may increase your chance that early or intermediate macular degeneration will progress to the more severe form of the disease.
• Cardiovascular disease. If you have had diseases that affected your heart and blood vessels, you may be at higher risk of macular degeneration.

Complications

People whose dry macular degeneration has progressed to central vision loss may experience depression or visual hallucinations. And dry macular degeneration may progress to wet macular degeneration, which can cause rapid vision loss if left untreated.

Prevention

The following measures may help reduce your risk of developing dry macular degeneration:

• Have routine eye exams. Ask your eye doctor how often you need to undergo routine eye exams. A dilated eye exam can identify macular degeneration.
• Manage your other medical conditions. For example, if you have cardiovascular disease or high blood pressure, take your medication and follow your doctor's instructions for controlling the condition.
• Don't smoke. Smokers are more likely to develop macular degeneration than are nonsmokers. Ask your doctor for help to stop smoking.
• Maintain a healthy weight and exercise regularly. If you need to lose weight, reduce the number of calories you eat and increase the amount of exercise you get each day. Maintain a healthy weight by exercising regularly and controlling your diet.
• Choose a diet rich in fruits and vegetables. Choose a healthy diet that's full of a variety of fruits and vegetables. These foods contain antioxidant vitamins that reduce your risk of developing macular degeneration.
• Include fish in your diet. Omega-3 fatty acids, which are found in fish, may reduce the risk of macular degeneration. Nuts, such as walnuts, also contain omega-3 fatty acids.

Read about diagnosis and treatment.

Eye floaters are spots in your vision. They may look to you like black or gray specks, strings, or cobwebs that drift about when you move your eyes and appear to dart away when you try to look at them directly.

Most eye floaters are caused by age-related changes that occur as the jelly-like substance (vitreous) inside your eyes becomes more liquid. Microscopic fibers within the vitreous tend to clump and can cast tiny shadows on your retina. The shadows you see are called floaters.

If you notice a sudden increase in eye floaters, contact an eye specialist immediately — especially if you also see light flashes or lose your peripheral vision. These can be symptoms of an emergency that requires prompt attention.

Symptoms

Symptoms of eye floaters may include:

• Small shapes in your vision that appear as dark specks or knobby, transparent strings of floating material
• Spots that move when you move your eyes, so when you try to look at them, they move quickly out of your visual field
• Spots that are most noticeable when you look at a plain bright background, such as a blue sky or a white wall
• Small shapes or strings that eventually settle down and drift out of the line of vision

When to see a doctor

Contact an eye specialist immediately if you notice:

• Many more eye floaters than usual
• A sudden onset of new floaters
• Flashes of light in the same eye as the floaters
• Darkness on any side or sides of your vision (peripheral vision loss)

These painless symptoms could be caused by a retinal tear, with or without a retinal detachment — a sight-threatening condition that requires immediate attention.

Causes

Eye floaters may be caused by the normal aging process or as a result from other diseases or conditions:

• Age-related eye changes. As you age, the vitreous, or jelly-like substance filling your eyeballs and helping them to maintain their round shape, changes. Over time, the vitreous partially liquefies — a process that causes it to pull away from the eyeball's interior surface. As the vitreous shrinks and sags, it clumps and gets stringy. This debris blocks some of the light passing through the eye, casting tiny shadows on your retina that are seen as floaters.
• Inflammation in the back of the eye. Posterior uveitis is inflammation in the layers of the uvea in the back of the eye. This condition can cause the release of inflammatory debris into the vitreous that are seen as floaters. Posterior uveitis may be caused by infection, inflammatory diseases or other causes.
• Bleeding in the eye. Bleeding into the vitreous can have many causes, including diabetes, hypertension, blocked blood vessels and injury. Blood cells are seen as floaters.
• Torn retina. Retinal tears can occur when a sagging vitreous tugs on the retina with enough force to tear it. Without treatment, a retinal tear may lead to retinal detachment — an accumulation of fluid behind the retina that causes it to separate from the back of your eye. Untreated retinal detachment can cause permanent vision loss.
• Eye surgeries and eye medications. Certain medications that are injected into the vitreous can cause air bubbles to form. These bubbles are seen as shadows until your eye absorbs them. Certain vitreoretinal surgeries add silicone oil bubbles into the vitreous that can also be seen as floaters.

Risk factors

Factors that can increase your risk of floaters include:

• Age over 50
• Nearsightedness
• Eye trauma
• Complications from cataract surgery
• Diabetic retinopathy
• Eye inflammation

Read about diagnosis and treatment.

Eyestrain is a common condition that occurs when your eyes get tired from intense use, such as while driving long distances or staring at computer screens and other digital devices.

Eyestrain can be annoying. But it usually isn't serious and goes away once you rest your eyes or take other steps to reduce your eye discomfort. In some cases, signs and symptoms of eyestrain can indicate an underlying eye condition that needs treatment.

Symptoms

Eyestrain signs and symptoms include:

• Sore, tired, burning or itching eyes
• Watery or dry eyes
• Blurred or double vision
• Headache
• Sore neck, shoulders or back
• Increased sensitivity to light
• Difficulty concentrating
• Feeling that you cannot keep your eyes open

When to see a doctor

See your doctor if self-care steps don't relieve your eyestrain.

Causes

Common causes of eyestrain include:

• Looking at digital device screens
• Reading without pausing to rest your eyes
• Driving long distances and doing other activities involving extended focus
• Being exposed to bright light or glare
• Straining to see in very dim light
• Having an underlying eye problem, such as dry eyes or uncorrected vision (refractive error)
• Being stressed or fatigued
• Exposure to dry moving air from a fan, heating or air-conditioning system

Computer use

Extended use of computers and other digital devices is one of the most common causes of eyestrain. The American Optometric Association calls this computer vision syndrome, or digital eyestrain. People who look at screens two or more hours in a row every day are at greatest risk of this condition.

Computer use strains eyes more than reading print material because people tend to:

• Blink less while using computers (blinking is key to moistening the eyes)
• View digital screens at less-than-ideal distances or angles
• Use devices that have glare or reflection
• Use devices with poor contrast between the text and the background

In some cases, an underlying eye problem, such as eye muscle imbalance or uncorrected vision, can cause or worsen computer eyestrain.

Some other factors that can make the condition worse include:

• Glare on your screen
• Poor posture
• Setup of your computer work station
• Circulating air, such as from air conditioning or a nearby fan

Complications

Eyestrain doesn't have serious or long-term consequences, but it can be aggravating and unpleasant. It can make you tired and reduce your ability to concentrate.

Learn about diagnosis and treatment.

Farsightedness (hyperopia) is a common vision condition in which you can see distant objects clearly, but objects nearby may be blurry.

The degree of your farsightedness influences your focusing ability. People with severe farsightedness may see clearly only objects a great distance away, while those with mild farsightedness may be able to clearly see objects that are closer.

Farsightedness usually is present at birth and tends to run in families. You can easily correct this condition with eyeglasses or contact lenses. Another treatment option is surgery.

Symptoms

Farsightedness may mean:

• Nearby objects may appear blurry
• You need to squint to see clearly
• You have eyestrain, including burning eyes, and aching in or around the eyes
• You experience general eye discomfort or a headache after a prolonged interval of conducting close tasks, such as reading, writing, computer work or drawing

When to see a doctor

If your degree of farsightedness is pronounced enough that you can't perform a task as well as you wish, or if your quality of vision detracts from your enjoyment of activities, see an eye doctor. He or she can determine the degree of your farsightedness and advise you of options to correct your vision.

Since it may not always be readily apparent that you're having trouble with your vision, the American Academy of Ophthalmology recommends the following intervals for regular eye exams:

Adults

If you don't wear glasses or contacts, have no symptoms of eye trouble and are at a low risk of developing eye diseases, have a baseline eye exam around age 40. Then have an exam at the following intervals:

• Every two to four years between 40 and 54 years
• Every one to three years between 55 and 64 years
• Every one to two years beginning at age 65

If you're at high risk of certain eye diseases, such as glaucoma, the frequency of visits should be increased to:

• Every two to four years up to age 40
• Every one to three years between 40 and 54 years
• Every one to two years from age 55 onward

If you wear glasses or contacts, you'll likely need to have your eyes checked every year. Ask your eye doctor how frequently you need to schedule your appointments. But if you notice any problems with your vision, schedule an appointment with your eye doctor as soon as possible, even if you've recently had an eye exam. Blurred vision, for example, may suggest you need a prescription change, or it could be a sign of another problem.

Children and adolescents

Children need to be screened for eye disease and have their vision tested by a pediatrician, an ophthalmologist or another trained screener during the newborn period, and then at every routine health exam throughout early childhood.

Additionally, it's recommended that school-age children be screened at school or through community programs approximately every two years to check for vision problems.

Causes

Your eye has two parts that focus images:

• The cornea, the clear front surface of your eye
• The lens, a clear structure inside your eye that changes shape to help focus on objects

In a perfectly shaped eye, each of these focusing elements has a perfectly smooth curvature, like the surface of a marble. A cornea and lens with such curvature bend (refract) all incoming light to make a sharply focused image directly on the retina, at the back of your eye.

A refractive error

If your cornea or lens isn't evenly and smoothly curved, light rays aren't bent (refracted) properly, and you have a refractive error. Farsightedness is one type of refractive error.

Farsightedness occurs when your cornea is curved too little or your eye is shorter than normal. Instead of being focused precisely on your retina, light is focused behind your retina, resulting in a blurry appearance for close-up objects.

Other refractive errors

In addition to farsightedness, other refractive errors include:

• Nearsightedness (myopia). This occurs when your cornea is curved too much or your eye is longer than normal, which makes faraway objects blurry and close objects clear.
• Astigmatism. This occurs when your cornea or lens is curved more steeply in one direction than in another. Uncorrected astigmatism blurs your vision.

Complications

Farsightedness can be associated with several problems, such as:

• Crossed eyes. Some children with farsightedness may develop crossed eyes. Specially designed eyeglasses that correct for part or all of the farsightedness may effectively treat this problem.
• Reduced quality of life. Uncorrected farsightedness can affect your quality of life. You might not be able to perform a task as well as you wish. And your limited vision may detract from your enjoyment of day-to-day activities. In children, untreated farsightedness may cause learning problems.
• Eyestrain. Uncorrected farsightedness may cause you to squint or strain your eyes to maintain focus. This can lead to eyestrain and headaches.
• Impaired safety. For your own safety and that of others, don't drive or operate mechanical equipment if you have an uncorrected vision problem.

Prevention

You can't prevent farsightedness, but you can help protect your eyes and your vision. Follow these steps:

• Have your eyes checked. Regardless of how well you see, have your eyes checked regularly.
• Control chronic health conditions. Certain conditions, such as diabetes and high blood pressure, can affect your vision if you don't receive proper treatment.
• Recognize symptoms. Sudden loss of vision in one eye, sudden hazy or blurred vision, flashes of light, black spots, or halos or rainbows around lights may signal a serious medical problem. Seek immediate medical care if you experience any of these signs or symptoms.
• Protect your eyes from the sun. Wear sunglasses that block ultraviolet (UV) radiation. This is especially important if you spend long hours in the sun or are taking a prescription medication that increases your sensitivity to UV radiation.
• Eat healthy foods. Maintain a healthy diet that contains plenty of fruits and vegetables. A diet containing these foods is necessary to maintain a healthy retina, and likely slows the progression of macular degeneration. Eat dark leafy foods and bright-colored fruits and vegetables, such as spinach, kale, carrots, yams and cantaloupe.
• Don't smoke. Smoking can adversely affect your eye health. Smoking is one of the most important preventable risk factors for developing macular degeneration. Use the right glasses. The right glasses optimize your vision. Having regular exams will ensure that your eyeglass prescription is correct.
• Use good lighting. Turning up the lights can improve contrast and help you see better.

Learn about diagnosis and treatment.

Glaucoma is a group of eye conditions that damage the optic nerve, which is vital to good vision. This damage is often caused by an abnormally high pressure in your eye.

Glaucoma is one of the leading causes of blindness in the United States. It can occur at any age but is more common in older adults.

The most common form of glaucoma has no warning signs. The effect is so gradual that you may not notice a change in vision until the condition is at an advanced stage.

Vision loss due to glaucoma can't be recovered. So it's important to have regular eye exams that include measurements of your eye pressure. If glaucoma is recognized early, vision loss can be slowed or prevented. If you have the condition, you'll generally need treatment for the rest of your life.

Symptoms

The signs and symptoms of glaucoma vary depending on the type and stage of your condition. For example:

Open-angle glaucoma

• Patchy blind spots in your side (peripheral) or central vision, frequently in both eyes
• Tunnel vision in the advanced stages

Acute angle-closure glaucoma

• Severe headache
• Eye pain
• Nausea and vomiting
• Blurred vision
• Halos around lights
• Eye redness

If left untreated, glaucoma will eventually cause blindness. Even with treatment, about 15 percent of people with glaucoma become blind in at least one eye within 20 years.

When to see a doctor

Seek immediate medical care

Promptly go to an emergency room or an eye doctor's (ophthalmologist's) office if you experience some of the symptoms of acute angle-closure glaucoma, such as severe headache, eye pain and blurred vision.

Schedule eye exams

Open-angle glaucoma gives few warning signs until permanent damage has already occurred. Regular eye exams are the key to detecting glaucoma early enough to successfully slow or prevent vision loss.

The American Academy of Ophthalmology recommends glaucoma screening:

• Every four years beginning at age 40 if you don't have any glaucoma risk factors
• Every two years if you're at high risk or over 65

Causes

Glaucoma is the result of damage to the optic nerve. As this nerve gradually deteriorates, blind spots develop in your visual field. For reasons that doctors don't fully understand, this nerve damage is usually related to increased pressure in the eye.

Elevated eye pressure is due to a buildup of a fluid (aqueous humor) that flows throughout your eye. This fluid normally drains into the front of the eye (anterior chamber) through tissue (trabecular meshwork) at the angle where the iris and cornea meet. When fluid is overproduced or the drainage system doesn't work properly, the fluid can't flow out at its normal rate and pressure builds up.

Glaucoma tends to run in families. In some people, scientists have identified genes related to high eye pressure and optic nerve damage.

The types of glaucoma include the following:

Open-angle glaucoma

Open-angle glaucoma is the most common form of the disease. The drainage angle formed by the cornea and iris remains open, but the trabecular meshwork is partially blocked. This causes pressure in the eye to gradually increase. This pressure damages the optic nerve. It happens so slowly that you may lose vision before you're even aware of a problem.

Angle-closure glaucoma

Angle-closure glaucoma, also called closed-angle glaucoma, occurs when the iris bulges forward to narrow or block the drainage angle formed by the cornea and iris. As a result, fluid can't circulate through the eye and pressure increases. Some people have narrow drainage angles, putting them at increased risk of angle-closure glaucoma.

Angle-closure glaucoma may occur suddenly (acute angle-closure glaucoma) or gradually (chronic angle-closure glaucoma). Acute angle glaucoma is a medical emergency. It can be triggered by sudden dilation of your pupils.

Normal-tension glaucoma

In normal-tension glaucoma, your optic nerve becomes damaged even though your eye pressure is within the normal range. No one knows the exact reason for this. You may have a sensitive optic nerve, or you may have less blood being supplied to your optic nerve. This limited blood flow could be caused by atherosclerosis — the buildup of fatty deposits (plaques) in the arteries — or other conditions that impair circulation.

Glaucoma in children

It's possible for infants and children to have glaucoma. It may be present from birth or developed in the first few years of life. The optic nerve damage may be caused by drainage blockages or an underlying medical condition.

Pigmentary glaucoma

In pigmentary glaucoma, pigment granules from your iris build up in the drainage channels, slowing or blocking fluid exiting your eye. Activities such as jogging sometimes stir up the pigment granules, depositing them on the trabecular meshwork and causing intermittent pressure elevations.

Risk factors

Because chronic forms of glaucoma can destroy vision before any signs or symptoms are apparent, be aware of these risk factors:

• Having high internal eye pressure (intraocular pressure)
• Being over age 60
• Being black or Hispanic
• Having a family history of the condition
• Having certain medical conditions, such as diabetes, heart disease, high blood pressure and sickle cell anemia
• Having certain eye conditions, such as nearsightedness
• Having had an eye injury or certain types of eye surgery
• Early estrogen deficiency, such as can occur after removal of both ovaries (bilateral oophorectomy) before age 43
• Taking corticosteroid medications, especially eyedrops, for a long time

Prevention

You may not be able to prevent glaucoma. But these self-care steps can help you detect it early, limit vision loss or slow its progress.

• Get regular eye care. Regular comprehensive eye exams can help detect glaucoma in its early stages before irreversible damage occurs. As a general rule, have comprehensive eye exams every four years beginning at age 40 and every two years from age 65. You may need more frequent screening if you're at high risk of glaucoma. Ask your doctor to recommend the right screening schedule for you.
• Know your family's eye health history. Glaucoma tends to run in families. If you're at increased risk, you may need more frequent screening.
• Exercise safely. Regular, moderate exercise may help prevent glaucoma by reducing eye pressure. Talk with your doctor about an appropriate exercise program.
• Take prescribed eyedrops regularly. Glaucoma eyedrops can significantly reduce the risk that high eye pressure will progress to glaucoma. To be effective, eyedrops prescribed by your doctor need to be used regularly even if you have no symptoms.
• Wear eye protection. Serious eye injuries can lead to glaucoma. Wear eye protection when using power tools or playing high-speed racket sports on enclosed courts.

Learn about diagnosis and treatment.

Lazy eye (amblyopia) is reduced vision in one eye caused by abnormal visual development early in life. The weaker — or lazy — eye often wanders inward or outward.

Amblyopia generally develops from birth up to age 7 years. It is the leading cause of decreased vision in one eye among children. Rarely, lazy eye affects both eyes.

Early diagnosis and treatment can help prevent long-term problems with your child's vision. Lazy eye can usually be corrected with glasses or contact lenses, or eye patches. Sometimes surgery is required.

Symptoms

Signs and symptoms of lazy eye include:

• An eye that wanders inward or outward
• Eyes that appear to not work together
• Poor depth perception
• Squinting or shutting an eye
• Head tilting
• Abnormal results of vision screening tests

Sometimes lazy eye is not evident without an eye exam.

When to see a doctor

See your child's doctor if you notice his or her eye wandering at any time after the first few weeks of life. A vision check is especially important if there's a family history of crossed eyes, childhood cataracts or other eye conditions.

For all children, a complete eye exam is recommended between ages 3 and 5.

Causes

Lazy eye develops because of abnormal visual experience early in life that changes the nerve pathways between a thin layer of tissue (retina) at the back of the eye and the brain. The weaker eye receives fewer visual signals. Eventually, the ability of the eyes to work together decreases, and the brain suppresses or ignores input from the weaker eye.

Anything that blurs a child's vision or causes the eyes to cross or turn out may result in lazy eye. Common causes of the condition include:

• Muscle imbalance (strabismus). The most common cause of lazy eye is an imbalance in the muscles that position the eyes. This imbalance can cause the eyes to cross in or turn out, and prevents them from tracking together in a coordinated way.
• Difference in sharpness of vision between the eyes (refractive anisometropia). A significant difference between the prescriptions in each eye — often due to farsightedness but sometimes to nearsightedness or an imperfection on the surface of the eye called astigmatism — can result in lazy eye. Glasses or contact lenses are typically used to correct these refractive problems. In some children lazy eye is caused by a combination of strabismus and refractive problems.
• Deprivation. Any problem with one eye — such as a cloudy area in the lens (cataract) — can deprive a child of clear vision in that eye. Deprivation amblyopia in infancy requires urgent treatment to prevent permanent vision loss. Deprivation amblyopia often results in the most severe amblyopia.

Risk factors

Factors associated with an increased risk of lazy eye include:

• Premature birth
• Small size at birth
• Family history of lazy eye
• Developmental disabilities

Complications

Untreated, lazy eye can cause permanent vision loss. Lazy eye is the cause of permanent vision loss in 2.9 percent of adults.

Read about diagnosis and treatment.

Nearsightedness (myopia) is a common vision condition in which you can see objects near to you clearly, but objects farther away are blurry.

Nearsightedness may develop gradually or rapidly, often worsening during childhood and adolescence. Nearsightedness tends to run in families.

A basic eye exam can confirm nearsightedness. You can easily correct the condition with eyeglasses or contact lenses. Another treatment option for nearsightedness is surgery.

Symptoms

Nearsightedness symptoms may include:

• Blurry vision when looking at distant objects
• The need to squint or partially close the eyelids to see clearly
• Headaches caused by eyestrain
• Difficulty seeing while driving a vehicle, especially at night (night myopia)

Nearsightedness is often first detected during childhood and is commonly diagnosed between the early school years through the teens. A child with nearsightedness may:

• Persistently squint
• Need to sit closer to the television, movie screen or the front of the classroom
• Seem to be unaware of distant objects
• Blink excessively
• Rub his or her eyes frequently

When to see a doctor

If your difficulty clearly seeing things that are far away is pronounced enough that you can't perform a task as well as you wish, or if the quality of your vision detracts from your enjoyment of activities, see an eye doctor. He or she can determine the degree of your nearsightedness and advise you of your options to correct your vision.

Seek emergency medical care if you experience a sudden onset of flashes of floaters or a shadow covering part of your field of vision. These are warnings signs of retinal detachment, which is a rare complication of myopia. Retinal detachment is a medical emergency, and time is critical.

Regular eye exams

Since it may not always be readily apparent that you're having trouble with your vision, the American Academy of Ophthalmology recommends the following intervals for regular eye exams:

Adults

If you're at high risk of certain eye diseases, such as glaucoma, get an eye exam every two to four years up to age 40, then every one to three years between 40 and 54, and every one to two years beginning at age 55.

If you don't wear glasses or contacts, have no symptoms of eye trouble, and are at a low risk of developing eye diseases, such as glaucoma, get an eye exam at the following intervals.

• An initial exam at 40
• Every two to four years between ages 40 and 54
• Every one to three years between ages 55 and 64
• Every one to two years beginning at age 65

If you wear glasses or contacts, you'll likely need to have your eyes checked regularly. Ask your eye doctor how frequently you need to schedule your appointments. But, if you notice any problems with your vision, schedule an appointment with your eye doctor as soon as possible, even if you've recently had an eye exam. Blurred vision, for example, may suggest you need a prescription change, or it could be a sign of another problem.

Children and adolescents

Children need to be screened for eye disease and have their vision tested by a pediatrician, an ophthalmologist or another trained screener at the following ages and intervals.

• During the newborn period
• At well-child visits until school age
• During school years, every one to two years at well-child visits, or through school or public screenings

Causes

Nearsightedness usually occurs when your eye is too long or has a cornea that's curved too steeply. This causes the light rays entering each eye to focus in front of the retina, instead of on the retina, leading to blurry images. The exact reason for some people developing longer eyes is unknown, but it may be related to genetics or environmental conditions.

Normal vision

To focus the images it sees, your eye relies on two critical parts:

• The cornea, the clear front surface of your eye
• The crystalline lens, a clear structure inside your eye that changes shape to help focus objects

In a normally shaped eye, each of these focusing elements has a perfectly smooth curvature like the surface of a smooth rubber ball. A cornea and lens with such curvature bend (refract) all incoming light in such a way as to make a sharply focused image on the retina, at the back of your eye.

A refractive error

However, if your cornea or lens isn't evenly and smoothly curved, light rays aren't refracted properly, and you have a refractive error. Nearsightedness is one type of refractive error. Instead of being focused precisely on your retina, light is focused in front of your retina, resulting in a blurry appearance of distant objects.

Other refractive errors

In addition to nearsightedness, other refractive errors include:

• Farsightedness (hyperopia). This occurs when your cornea is curved too little or your eye is shorter from front to back than normal. The effect is the opposite of nearsightedness. In adults, both near and distant objects are blurred.
• Astigmatism. This occurs when your cornea or lens is curved more steeply in one direction than in another. Uncorrected astigmatism blurs your vision.

Risk factors

Certain risk factors may increase the likelihood of developing nearsightedness, such as:

• Family history. Nearsightedness tends to run in families. If one of your parents is nearsighted, your risk of developing the condition is increased. The risk is even higher if both parents are nearsighted.
• Reading. People who do a lot of reading may be at increased risk of myopia.
• Environmental conditions. Some studies support the idea that a lack of time spent outdoors may increase the chances of developing myopia.

Complications

Nearsightedness may be associated with several complications, such as:

• Reduced quality of life. Uncorrected nearsightedness can affect your quality of life. You might not be able to perform a task as well as you wish. And your limited vision may detract from your enjoyment of day-to-day activities.
• Eyestrain. Uncorrected nearsightedness may cause you to squint or strain your eyes to maintain focus. This can lead to eyestrain and headaches.
• Impaired safety. Your own safety and that of others may be jeopardized if you have an uncorrected vision problem. This could be especially serious if you are driving a car or operating heavy equipment.
• Other eye problems. Severe nearsightedness puts you at a slightly increased risk of retinal detachment, glaucoma and cataracts.

Read about diagnosis and treatment.

Presbyopia is the gradual loss of your eyes' ability to focus on nearby objects. It's a natural, often annoying part of aging. Presbyopia usually becomes noticeable in your early to mid-40s and continues to worsen until around age 65.

You may become aware of presbyopia when you start holding books and newspapers at arm's length to be able to read them. A basic eye exam can confirm presbyopia. You can correct the condition with eyeglasses or contact lenses. You might also consider surgery.

Symptoms

Presbyopia develops gradually. You may first notice these signs and symptoms after age 40:

• A tendency to hold reading material farther away to make the letters clearer
• Blurred vision at normal reading distance
• Eyestrain or headaches after reading or doing close-up work

You may notice these symptoms are worse if you are tired or are in an area with dim lighting.

When to see a doctor

See an eye doctor if blurry close-up vision is keeping you from reading, doing close-up work or enjoying other normal activities. He or she can determine whether you have presbyopia and advise you of your options.

Seek immediate medical care if you:

• Have a sudden loss of vision in one eye with or without eye pain
• Experience sudden hazy or blurred vision
• See flashes of light, black spots or halos around lights
• Have double vision

Causes

Anatomy of the eye Anatomy of the eye Eyeball with point of focus for presbyopia Presbyopia To form an image, your eye relies on the cornea and the lens to focus the light reflected from objects. The closer the object, the more the lens flexes.

• The cornea is the clear, dome-shaped front surface of your eye.
• The lens is a clear structure about the size and shape of an M&M's candy.
• Both of these structures bend (refract) light entering your eye to focus the image on the retina, located on the inside back wall of your eye.

The lens, unlike the cornea, is somewhat flexible and can change shape with the help of a circular muscle that surrounds it. When you look at something at a distance, the circular muscle relaxes. When you look at something nearby, the muscle constricts, allowing the relatively elastic lens to curve and change its focusing power.

Presbyopia is caused by a hardening of the lens of your eye, which occurs with aging. As your lens becomes less flexible, it can no longer change shape to focus on close-up images. As a result, these images appear out of focus.

Risk factors

Certain factors can make you more likely to develop presbyopia, including:

• Age. Age is the greatest risk factor for presbyopia. Almost everyone experiences some degree of presbyopia after age 40.
• Other medical conditions. Being farsighted or having certain diseases — such as diabetes, multiple sclerosis or cardiovascular diseases — can increase your risk of premature presbyopia, which is presbyopia in people younger than 40.
• Drugs. Certain drugs are associated with premature presbyopic symptoms, including antidepressants, antihistamines and diuretics.

Read about diagnosis and treatment.

Wet macular degeneration is a chronic eye disease that causes blurred vision or a blind spot in your visual field. It's generally caused by abnormal blood vessels that leak fluid or blood into the macula (MAK-u-luh). The macula is in the part of the retina responsible for central vision.

Wet macular degeneration is one of two types of age-related macular degeneration. The other type — dry macular degeneration — is more common and less severe. The wet type always begins as the dry type.

Early detection and treatment of wet macular degeneration may help reduce vision loss and, in some instances, recover vision.

Symptoms

Wet macular degeneration symptoms usually appear suddenly and worsen rapidly. They may include:

• Visual distortions, such as straight lines seeming bent
• Reduced central vision in one or both eyes
• Decreased intensity or brightness of colors
• A well-defined blurry spot or blind spot in your field of vision
• A general haziness in your overall vision
• Abrupt onset and rapid worsening of symptoms

Macular degeneration doesn't affect side (peripheral) vision, so it rarely causes total blindness.

When to see a doctor

See your eye doctor if:

• You notice changes in your central vision
• Your ability to see colors and fine detail becomes impaired

These changes may be the first indication of macular degeneration, particularly if you're older than age 50.

Causes

Parts of the inner eye Inner eye No one knows the exact cause of wet macular degeneration, but it develops in people who have had dry macular degeneration. Of all people with age-related macular degeneration, about 10 percent have the wet form.

Wet macular degeneration can develop in different ways:

• Vision loss caused by abnormal blood vessel growth. Sometimes abnormal new blood vessels grow from the choroid under and into the macula (choroidal neovascularization). The choroid is the layer of blood vessels between the retina and the outer, firm coat of the eye (sclera). These abnormal blood vessels may leak fluid or blood, interfering with the retina's function.
• Vision loss caused by fluid buildup in the back of the eye. When fluid leaks from the choroid, it can collect between the choroid and a thin cell layer called the retinal pigment epithelium. This may cause a bump in the macula, resulting in vision loss.

Risk factors

Factors that may increase your risk of macular degeneration include:

• Age. This disease is most common in people over 65.
• Family history. This disease has a hereditary component. Researchers have identified several genes related to developing the condition.
• Smoking. Smoking cigarettes or being regularly exposed to smoke significantly increases your risk of macular degeneration.
• Obesity. Research indicates that being obese increases the chance that early or intermediate macular degeneration will progress to a more severe form of the disease.
• Cardiovascular disease. If you have diseases that affect your heart and blood vessels, you may be at higher risk of macular degeneration.

Complications

People whose wet macular degeneration has progressed to central vision loss may experience depression or visual hallucinations (Charles Bonnet syndrome).

Prevention

The following measures may help reduce your risk of developing wet macular degeneration:

• Have routine eye exams. Ask your eye doctor how often you need to undergo routine eye exams. A dilated eye exam can identify macular degeneration. In between checkups, you can do a self-assessment of your vision using an Amsler grid.
• Manage your other medical conditions. For example, if you have cardiovascular disease or high blood pressure, take your medication and follow your doctor's instructions for controlling the condition.
• Don't smoke. Smokers are more likely to develop macular degeneration than are nonsmokers. Ask your doctor for help to stop smoking.
• Maintain a healthy weight and exercise regularly. If you need to lose weight, reduce the number of calories you eat and increase the amount of exercise you get each day. Maintain a healthy weight by exercising regularly and controlling your diet.
• Choose a healthy diet. Include fruits, leafy greens, nuts and fish high in omega-3 fatty acids, such as salmon.
• Take certain nutritional supplements. If you have intermediate or advanced macular degeneration, taking supplements with high levels of vitamins C and E, zinc and copper may reduce the risk of vision loss, the American Academy of Ophthalmology says. Ask your doctor if taking supplements is right for you.

Read about diagnosis and treatment.