VISUAL IMPAIRMENT AND ITS CAUSES
There are many different causes of blindness and visual impairment, including aging, disease, congenital problems and accidents. In the United States, the major causes of blindness and severe visual impairment are age-related macular degeneration, glaucoma, diabetic retinopathy, retinitis pigmentosa, and to some degree, cataracts.
Macular degeneration is an eye condition that affects the retina, a thin layer of tissue that covers the back inside wall of the eye. The central portion of the retina is called the macula, and it is responsible for central vision which is used to see details. Thus, this eye condition affects a person's ability to read, identify faces, etc. Macular degeneration does not result in total blindness. New treatments may slow the progression of macular degeneration, but cannot reverse the condition.
Glaucoma is an eye condition that can cause blindness without any symptoms or pain. Glaucoma causes progressive damage to the optic nerve, often due to high pressure inside the eye. This damage causes loss of side vision and can eventually result in blindness. Only an eye examination can tell whether glaucoma is present, and if diagnosed in its early stages, treatment with drops and other medications can be most effective.
Normal vision Glaucoma
Diabetic retinopathy is a disease of the eye caused when the small blood vessels in the retina begin to weaken or get blocked. The disease's effect on vision can range from a distortion similar to looking through water, to dark spots throughout the visual field. Eventually the retina can become detached resulting in severe vision loss or blindness. For people with diabetes, the risk for this disease can be lowered by controlling blood sugar levels and diet.
Normal vision Diabetic retinopathy
Retinitis Pigmentosa (RP) is the name given to a group of eye diseases that are genetic. RP affects the part of the eye that is sensitive to light. RP develops slowly and severe vision loss may take many years. An early symptom is night blindness. The next symptom is a loss of side vision, which worsens over time until all side vision is lost. RP can lead to total blindness. There is no cure at this time.
A cataract is a clouding of the lens in the eye, usually associated with aging. Surgery to remove the damaged lens is a highly effective method of restoring sight to a person with cataracts. Some individuals experience visual impairment when treatment is complicated by other health conditions.