Cataract

A cataract is a clouding of the eye's lens that causes loss of vision. Age-related cataract is the most common type.

Causes

Researchers suspect that there are several causes of cataract, such as smoking and diabetes. Or, it may be that the protein in the lens just changes from the wear and tear it takes over the years. Sunlight and diet have also been linked to early development of cataract.

Cataract and Age

The term "age-related" is a little misleading. You don't have to be a senior citizen to get this type of cataract. People can have an age-related cataract in their 40s and 50s. But during middle age, most cataracts are small and do not effect vision. It is after age 60 that most cataracts steal vision.

Symptoms

A cataract starts out small. It has little effect on vision at first. You may notice that your vision blurs a little, like looking through a cloudy piece of glass. A cataract may make light from the sun or a lamp seem too bright, causing a glare. Or, you may notice when you drive at night that the oncoming headlights cause more glare than before. Also, colors may not appear as bright to you as they once did.

Age-Related Macular Degeneration

AMD is a common eye disease associated with aging that gradually destroys sharp, central vision. Central vision is needed for seeing objects clearly and for common daily tasks such as reading and driving. In some people, AMD advances so slowly that it will have little effect on their vision as they age. But in others, the disease progresses faster and may lead to a loss of vision in one or both eyes.

Types of AMD

Dry and wet are the two forms of AMD.
Ninety people have dry AMD. Scientists are still not sure what causes this. Studies suggest that an area of the retina becomes diseased, leading to slow breakdown of the light-sensing cells in the macula and a gradual loss of central vision. Wet AMD affects only ten percent of all people with AMD, but accounts for ninety percent of all blindness from the disease. As dry AMD worsens, new blood vessels may begin to grow and cause "wet" AMD. Because these new blood vessels tend to be fragile, they often leak blood and fluid under the macula. This causes rapid damage to the macula that can lead to the loss of central vision in a short period of time.

AMD and Age

Age is the greatest risk factor associated with AMD. Although AMD may occur during middle age, studies clearly show that people over age 60 at greater risk.

Symptoms

There is no pain associated with AMD.  The most common early sign of dry AMD is blurred vision. Often blurred vision will go away in brighter light. If the loss of these light-sensing cells becomes great, people may see a small - but growing - blind spot in the middle of their field of vision. The classic early symptom of wet AMD is when straight lines appear crooked. This results when fluid from the leaking blood vessels gathers and lifts the macula, distorting vision. A small blind spot may also appear in wet AMD, resulting in loss of one's central vision.

Glaucoma

Glaucoma is an eye disease in which the internal pressure of your eye rises to a point that the optic nerve is damaged. The pressure that builds up is due to a problem in the flow or drainage of fluid normally produced in your eye. Glaucoma is one of the leading causes of blindness in the U.S.

Causes

The exact cause of glaucoma is not known. In general, this drainage mechanism for fluid produced in your eyes can become blocked, or you may simply produce too much fluid and overwhelm this mechanism. This results in fluid building up within your eye and increasing pressure on the optic nerve. The nerve fibers and blood vessels in the optic nerve can easily be damaged by pressure.

Glaucoma and Age

Glaucoma most frequently occurs in individuals over the age of 40 and there is a hereditary tendency for the development of the disease in some families. Primary open-angle glaucoma is more common among blacks than whites, causes damage at an earlier age and leads to blindness at a much greater rate. There is also a greater tendency for glaucoma to develop in individuals who are nearsighted or who have diabetes.

Symptoms

The signs or symptoms of glaucoma can vary depending on the type. Primary open-angle glaucoma often develops gradually and painlessly. There are no early warning signs. It can gradually destroy your vision without you knowing it. The first indication may occur after some vision has already been lost. Acute angle-closure glaucoma, which results from a sudden blockage of drainage channels in your eye, causes a rapid build up of pressure accompanied by blurred vision, the appearance of colored rings around lights and pain or redness in the eyes.

Diabetes

Diabetic eye disease refers to a group of eye problems that people with diabetes may face as a complication of this disease. It can cause severe vision loss or even blindness. Diabetic eye disease may include: Diabetic retinopathy - damage to the blood vessels in the retina, Cataract and Glaucoma.

Diabetic Retinopathy

This disease 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. The longer someone has diabetes, the more likely he or she will get diabetic retinopathy. Nearly half of all people with diabetes will develop some degree of diabetic retinopathy during their lifetime.

Symptoms

Generally there are no symptoms in the early stages of the disease. Vision may not change until the disease becomes severe. Pain may not be present. Blurred vision may occur when the macula - the part of the retina that provides sharp, central vision - swells from the leaking fluid. This condition is called macular edema. If new vessels have grown on the surface of the retina, they can bleed into the eye, blocking vision. But, even in more advanced cases, the disease may progress a long way without symptoms.