Eye disorder that can occur with little warning is a cataract, which is clouding of the lens within the eye. The lens is composed of water and protein. The protein is arranged so that light can pass through and focus on the retina. If the protein clumps together, however, it starts to cloud over a small area of the lens. In time, this cloudy mass of protein — called a cataract — can grow larger, making it hard to see. That's when it becomes a problem.
Cataracts are painless. Often people with cataracts begin to complain about glare. "When these people have bright lights shined on them, their vision may drop rather dramatically." Colors may seem faded, and eyeglasses or contact lenses may need frequent changing. People with cataracts may need increased light to read.
If the cataract worsens surgery may be necessary to remove the cloudy lens and replace it with a new lens.
By the year 2020, there will be more than 12 million individuals in the 65 or older age group who will probably need treatment for cataracts.
Besides age, other factors that scientists believe may put individuals at greater risk for developing a cataract include heredity, alcohol use, smoking, long-term exposure to high levels of the sun's ultraviolet rays, some medications and systemic disorders such as diabetes.
The lens of eye is an important part of seeing clearly. It focuses light onto the retina. In cataract surgery, the affected lens is removed and, therefore usually needs to be replaced. Currently, there are three types of substitute lenses: an intraocular lens (IOL), a contact lens or cataract glasses. About 90 percent of people who need to replace their lens choose an IOL. Of them, about 90 percent achieve 20/40 vision or better.
Intraocular lens: An IOL is a clear synthetic lens that is placed in the eye during cataract surgery. It requires no care. With an IOL, patients have better vision and won't feel or see the new lens. A few people cannot have an IOL because they're sensitive to the material the lens is made of, their eye structure isn't suitable, or they have certain other eye diseases.
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