A cataract is a clouding of the eye's normally clear lens. It is not a film over the outside of the eye, as many people think. The lens is located inside the eye, behind the iris (the colored part of the eye), and helps to focus the light rays for clear vision. With age, and sometimes as a side effect of medications, the lens becomes clouded. This clouding of the lens results in blurred vision.
While cataracts often affect both eyes, sometimes only one eye is affected. It is common for one cataract to be more cloudy, resulting in poorer vision in one eye compared to the other. Most often, cataracts occur as a natural consequence of aging. Lens clouding forms to a greater or lesser degree in everyone with age. A family history increases the risk of cataracts. Cataracts are also caused by:
A comprehensive eye examination by an eye care professional (ophthalmologist or optometrist) can detect the presence and extent of a cataract. There can also be reasons other than cataract for worsened vision, including diseases of the cornea, retina or optic nerve. If another disease is present with a cataract, perfect vision may not be restored after cataract surgery. Cataract surgery involves removing the natural lens (that has become clouded) and replacing it with an artificial intraocular lens implant. Other areas of this website deal in detail with this subject.