Vision 101

While there are many health concerns that can damage and cause visual impairment, according to the National Eye Institute at the National Institutes of Health, age-related macular degeneration (AMD), glaucoma, cataract, and diabetic retinopathy are the most common eye diseases in Americans age 40 and over. The leading cause of blindness among White Americans is AMD, accounting for 54 percent of all blindness. Among African Americans, the leading causes of blindness are cataract and glaucoma. Among Hispanics, glaucoma is the most common cause of blindness.

What is age-related macular degeneration (AMD)
AMD is a common eye disease associated with aging that gradually destroys sharp, central vision that is needed for seeing objects clearly and for common daily tasks such as reading and driving. There are two forms of macular degeneration, dry and wet. The dry type is more common, slow in progression and, initially, less serious. The wet form is the second and more serious type of the disease.

Risk Factors
The greatest risk factor is age. Although AMD may occur during middle age, studies show that people over age 60 are clearly at greater risk than other age groups. Other risk factors include smoking, obesity, race, family history and gender (women appear to be at greater risk than men). The leading cause of blindness among White Americans is AMD, accounting for 54 percent of all blindness.

Signs and Symptoms of AMD
The most common early sign of dry AMD is blurred vision. The classic early symptom of wet AMD is that straight lines appear crooked.

Screening
AMD is detected during a comprehensive eye exam that includes:

1. Visual acuity test—this eye chart test measures how well you see at various distances.
2. Dilated eye exam—drops are placed in your eyes to widen, or dilate the pupils. Your eye care professional uses a special magnifying lens to examine your retina and optic nerve for signs of AMD and other eye problems. After the exam, your close-up vision may remain blurred for several hours.
3. Tonometry—an instrument measures the pressure inside the eye.

Treatment
No treatment now exists for dry AMD. Eye care professionals can treat some cases of wet AMD with laser surgery.

Cataracts

What is a Cataract?
A cataract is a clouding of the lens in the eye that affects vision. Most cataracts are related to aging. Cataracts are very common in older people. By age 80, more than half of all Americans either have a cataract or have had cataract surgery.

Risk Factors
The risk of cataract increases as you get older. Other risk factors for cataract include certain diseases (for example, diabetes); personal behavior (smoking, alcohol use) and the environment (prolonged exposure to ultraviolet sunlight).

Signs and Symptoms of Cataracts
The most common symptoms of a cataract are cloudy or blurry vision, poor night vision, double vision or multiple images in one eye, colors that seem faded, glare from headlights, lamps, or sunlight appearing too bright.

Screening
A cataract is detected during a comprehensive eye exam that includes:

1. Visual acuity test—this eye chart test measures how well you see at various distances.
2. Dilated eye exam—drops are placed in your eyes to widen, or dilate, the pupils. Your eye care professional uses a special magnifying lens to examine your retina and optic nerve for signs of AMD and other eye problems. After the exam, your close-up vision may remain blurred for several hours.
3. Tonometry—an instrument measures the pressure inside the eye.

Treatment
Cataract can be treated with surgery. Your eye care professional will remove your clouded lens and, in most cases, replace it with a clear, plastic lens. Cataract surgery is very successful in restoring vision. In fact, it is one of the most common surgeries performed in the United States, with over 1.5 million cataract surgeries done each year.

Diabetic Retinopathy

What is Diabetic Retinopathy
Diabetic retinopathy is a leading cause of blindness in American adults. It is caused by changes in the blood vessels of the retina. In some people with diabetic retinopathy, retinal blood vessels may swell and leak fluid. In other people, abnormal new blood vessels grow on the surface of the retina. These changes may result in vision loss or blindness.

Risk Factors
Anyone with diabetes is at risk for diabetic retinopathy. The longer someone has diabetes, the more likely he or she will get diabetic retinopathy. Between 40-45 percent of those with diagnosed diabetes have some degree of diabetic retinopathy.

Signs and symptoms of Diabetic Retinopathy You may not get any signs of diabetes retina damage or you may get one or more signs, including blurry or double vision; rings, flashing lights, or blank spots; dark or floating spots; pain or pressure in one or both of your eyes, and/or trouble seeing things out of the corners of your eyes.

Screening
If you have diabetes, you should have your eyes examined at least once a year. Your eyes should be dilated during the exam. That means eye drops are used to enlarge your pupils. This allows the eye care professional to see more of the inside of your eyes to check for signs of the disease.

Treatment
Your eye care professional may suggest laser surgery in which a strong light beam is aimed onto the retina. Laser surgery and appropriate follow-up care can reduce the risk of blindness by 90 percent. However, laser surgery often cannot restore vision that has already been lost.

Glaucoma

What is Glaucoma?
Glaucoma is an eye disease in which the normal fluid pressure inside the eyes slowly rises, leading to vision loss--or even blindness. Open-angle glaucoma is the most common form of the disease.

Risk factors
Although anyone can get glaucoma, some people are at higher risk. They include African Americans over age 40, everyone over age 60, especially Mexican Americans and people with a family history of glaucoma.

Signs and Symptoms of Glaucoma
At first, there are no symptoms. Vision stays normal, and there is no pain. However, as the disease progresses, a person with glaucoma may notice his or her side vision gradually failing. That is, objects in front may still be seen clearly, but objects to the side may be missed. As the disease worsens, the field of vision narrows and blindness results.

Screening
Many people may know of the "air puff" test or other tests used to measure eye pressure in an eye examination. But, this test alone cannot detect glaucoma. Glaucoma is found most often during an eye examination through dilated pupils. This means drops are put into the eyes during the exam to enlarge the pupils. This allows the eye care professional to see more of the inside of the eye to check for signs of glaucoma.

Treatment
Although open-angle glaucoma cannot be cured, it can usually be controlled. The most common treatments are medications and laser surgery.

For more information on eye health:

National Eye Institute

EyeCare America