Sight enables much of the interaction humans have with the environment and one another. As such, the development of blindness proves a devastating loss. The leading causes of blindness in the United States include cataracts, glaucoma and diabetic retinopathy. Regular eye exams and good eye care can significantly reduce the risk of blindness associated with each of these eye disorders.
Glaucoma
The National Eye Institute reports that glaucoma is a leading cause of blindness in the U.S. The vitreous fluid fills the eyeball. Structures within the eye continually produce and recycle this fluid. Malfunction in the mechanisms that control the production and recycling of vitreous fluid cause increased pressure within the eye, called glaucoma. Chronically increased pressure in the eye can slowly damage the optic nerve and may eventually lead to blindness.
Visual loss characteristically occurs first in the periphery. The area of functional vision narrows with disease progression. Because it is a painless disorder, glaucoma may go undetected without regular vision checkups. Eye drops, oral medications and eye surgery can control glaucoma in most people with the disorder.
Diabetic Retinopathy
Diabetic retinopathy is a progressive eye disease caused by abnormalities in the blood vessels of the eyes, triggered by diabetes mellitus. The blood vessel abnormalities occur in the retina, the specialized tissue at the back of the eye that captures perceived images and transforms them into electrical signals, which the brain interprets into meaningful visual information. The University of Michigan Kellogg Eye Center explains that retinal blood vessel damage leads to progressive scarring. The abnormal blood vessels may leak or rupture, causing bleeding within the eyes. Accumulated eye damage due to diabetic retinopathy may eventually cause blindness. Regular eye exams prove critically important for people with diabetes due to the lack of symptoms associated with early-stage diabetic retinopathy.
According to the National Eye Institute, 40 to 45 percent of people with diabetes mellitus have diabetic retinopathy. A variety of treatments can slow the progression of the condition, including rigorous management of blood glucose and high blood pressure.
Cataracts
The National Institutes of Health reports that more than 22 million people in the U.S. have cataracts, which is the leading cause of blindness worldwide. A cataract involves clouding of the eye lens. Similar to a camera lens, the eye lens focuses perceived images onto the retina at the back of the eye. Protein clumping within the lens or discoloration of the normally clear lens can cause blurry, dim vision. Visual loss progresses as the clumping or discoloration of the lens advances, eventually leading to blindness.
Factors that contribute to the development of cataracts include advancing age, smoking, diabetes mellitus, alcohol abuse and exposure to ultraviolet radiation from the sun. Surgical replacement of a severely clouded lens with an artificial lens reverses vision loss caused by a cataract.
