Diabetic retinopathy
Diabetic retinopathy, a common complication of diabetes, affects the blood vessels in the retina (the thin light-sensitive membrane that covers the back of the eye). It is due to the retina not receiving enough oxygen. If untreated, it may lead to blindness. If diagnosed and treated promptly, blindness is usually preventable. There are two types: nonproliferative and proliferative retinopathy. Nonproliferative retinopathy is the less severe type in which there may be hemorrhages (bleeding) in the retina and leakage of blood or serum causing a "wet retina." As a consequence vision may be diminished. Proliferative retinopathy is a more severe type of diabetic retinopathy. New abnormal fragile vessels develop on the surface of the retina and may grow toward the center of the eye. These vessels frequently bleed into the vitreous (the clear jelly in the center of the eye). Such bleeding episodes cause severe visual problems. Treatment is by laser surgery or surgery on the vitreous. These techniques can slow the progression of diabetic retinopathy and sometimes will reverse visual loss. However, damage done may be permanent. Diabetic retinopathy can often be prevented by lifestyle modification, including weight loss, dietary changes, and exercise. In addition, better control of high blood sugar decreases the incidence and the progression of diabetic retinopathy.Strabismus (crossed eyes)
Strabismus, also known as crossed eyes, is a condition in which the eyes don't look toward an object together. One of the eyes may look in or out or turn up or down. The danger with strabismus is that the brain may come to rely more on one eye than the other and the less-favored eye fails to develop properly, leading to blindness in that eye. The classic treatment for mild-to-moderate strabismus has long been an eyepatch covering the stronger eye, which forces the weaker eye to do enough work to catch up. Severe strabismus may require surgery.
Floaters
"Eye floaters" are deposits or condensation in the vitreous jelly of the eye. People use the term eye floaters to describe seeing floating spots within their vision when they look around. People describe eye floaters as spots, straight and curved lines, strings, or "O" or "C" shaped blobs. Some see a single floater while others may think they see hundreds. Floaters may be present in one or both eyes. The majority of eye floaters are caused by normal aging changes within the eye. However, a person developing symptoms of eye floaters should be checked by an ophthalmologist to make certain that there is no associated eye abnormality which requires treatment. Most floaters will fade over time and become less annoying or noticeable. Herbs, vitamins, and iodine-containing products have been touted as effective in decreasing eye floaters. However, none of these have been proven effective in clinical trials.
Farsightedness (hyperopia)
About one in four people in the U.S. have hyperopia or farsightedness, in which people have difficulty focusing on close objects. The occurrence of hyperopia increases with age; at least half of all people over the age of 65 have some degree of farsightedness. The condition occurs when light entering the eye focuses behind the retina instead of directly on it. An abnormally flat cornea or short eye can cause the light to be focused in this fashion. To correct hyperopia you must change the way the light rays bend when entering your eye. Glasses, contact lenses, or refractive surgery can all be used to correct farsightedness.
Nearsightedness (Myopia)
Nearsightedness affects 20%-30% of the population, but this eye disorder is easily corrected with eyeglasses, contact lenses or surgery. People who have myopia or nearsightedness have difficulty seeing distant objects, but can see objects that are near clearly. In people with myopia, the eyeball is too long or the cornea has too much curvature, so the light entering the eye is not focused correctly. Light rays of images focus in front of the retina, the light-sensitive part of the eye, rather than directly on the retina, causing blurred vision.
Astigmatism
Astigmatism is a common form of visual impairment in which an image is blurred due to an irregularity in the curvature of the front surface of the eye, the cornea. In astigmatism, the curve of the cornea is shaped more like an American football or a rugby ball rather than a normal spherical basketball. Astigmatism occurs in nearly everybody to some degree. Astigmatism can be hereditary and is often present at birth. It can also result from pressure from the eyelids on the cornea. Almost all degrees of astigmatism can be corrected with properly prescribed eyeglasses or contact lenses. For a person with only a slight degree of astigmatism, corrective lenses may not be needed at all, as long as other conditions such as nearsightedness or farsightedness are not present. Another method for correcting astigmatism is by changing the shape of the cornea through refractive laser eye surgery.
Color Blindness
When we see different colors, we are perceiving differences in the light that is reaching our eyes. The way we see different colors is something like the way we hear different sounds as being low or high. The colors of every rainbow always appear in the same order: red, orange, yellow, green, blue, indigo, and violet. The different colors in each part of the rainbow correspond to a different wavelength of light. Color blindness results from an absence or malfunction of certain color-sensitive cells in the retina. The retina is the nerve layer at the back of the eye that converts light into nerve signals that are sent to the brain. A person with color blindness has trouble seeing red, green, blue, or mixtures of these colors. Most color vision problems are inherited (genetic) and are present at birth. Other color vision problems are caused by aging, disease, injury to the eye (acquired color vision problems), optic nerve problems, or side effects of some medicines. Tests are used to measure the ability to recognize different colors with the most common test being the pseudoisochromatic plate test (also known as the Ishihara color test). The type of color vision problem you have can often be determined by which patterns you can and can't see in the various plates used for the test. Inherited color vision problems cannot be treated or corrected. Some acquired color vision problems can be treated, depending on the cause.
Proactive Eye Health
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