Discover Commonly Used Definitions
The following eye definitions, describe some of the most common eye-related issues.
Astigmatism is a vision condition that occurs when the front surface of your eye, the cornea, is slightly irregular in shape. This irregular shape prevents light from focusing properly on the back of your eye, the retina. As a result, your vision may be blurred at all distances.
A cataract is a clouding of the lens in the eye that affects vision. Most cataracts are found in persons over age 55, but they are also occasionally found in younger people. By age 80, more than half of all Americans either have a cataract or have had cataract surgery.
Conjunctivitis is an inflammation of the conjunctiva, the thin, transparent layer that lines the inner eyelid and covers the white part of the eye. The infectious type of Conjunctivitis, commonly called "pink eye", is caused by a contagious virus or bacteria.
Glaucoma is an eye disease in which the internal pressure in your eyes increases enough to damage the nerve fibers in your optic nerve and cause vision loss. The increase in pressure happens when the passages that normally allow fluid in your eyes to drain become clogged or blocked. The reasons that the passages become blocked are not known.
Farsightedness, or hyperopia, as it is medically termed, is a vision condition in which distant objects are usually seen clearly, but close ones do not come into proper focus. Farsightedness occurs if your eyeball is too short or the cornea has too little curvature, so light entering your eye is not focused correctly.
Macular degeneration is the leading cause of blindness in America. It results from changes to the macula, a portion of the retina that is responsible for clear, sharp vision, and is located at the back of the eye.
Nearsightedness, or myopia, as it is medically termed, is a vision condition in which near objects are seen clearly, but distant objects do not come into proper focus. Nearsightedness occurs if your eyeball is too long or the cornea has too much curvature, so the light entering your eye is not focused correctly.
Presbyopia is a vision condition in which the crystalline lens of your eye loses its flexibility, which makes it difficult for you to focus on close objects.
Strabismus occurs when one or both of your eyes turns in, out, up or down, and is usually caused by poor eye muscle control. This misalignment often first appears before age 21 months but may develop as late as age 6. This is one reason why the American Optometric Association recommends a comprehensive optometric examination before 6months and again at age 3.