What Is Cataracts?

The term cataract refers to a clouding or loss of transparency of the lens — normally a crystal clear structure located behind the pupil and iris, focuses light on the retina, much as the lens in a camera focuses light. As clouding progresses, light has difficulty passing through the lens. This results in dim, distorted or blurred images on the retina and decreased vision, similar to looking through a dirty window.

There is no way of predicting how rapidly a cataract will progress. Some develop slowly over a period of many years, while others progress rapidly. Some cataracts decrease distance vision, while others predominantly affect near vision, and still others affect both.

At present, no treatment will slow or stop the progression of a cataract.

Cause of Cataracts

Most cataracts seem to be the result of the aging process, and most occur in individuals over age 65. However, cataracts can occur at any age. The second most common age group affected is the very young. Their cataracts are congenital in nature. People on chronic doses of steroids (such as for asthma) and smokers are at higher risk. A cataract may be caused or accelerated by conditions such as injury, inflammation inside the eye, certain disorders of blood chemistry and some drugs.

Symptoms of Cataracts

Many people have early cataracts and are unaware of them. Early cataracts may affect the vision more in certain lighting conditions, either bright light or darkness. Common symptoms of early cataracts include glare, halos, and a marked decrease in vision while driving at night.

The mere presence of a cataract does not mean you need surgery. Depending on your own visual needs, a developing cataract may or may not interfere with your normal lifestyle. If you see well enough to do most of the things you want to do, then you most likely do not need to have surgery. On the other hand, if your decreased vision interferes significantly with your lifestyle, surgery may be beneficial.

Cataract surgery can be done at any time and at any age. In the vast majority of cases, it is an elective procedure.

Diagnosis of Cataracts

Cataracts can be diagnosed through various tests performed by an ophthalmologist. These tests may include the standard ophthalmic exam, which examines the patient's visual acuity, or the slit lamp examination, which examines the front structure of the eye. Although moderately rare, other tests may also be performed, including the glare test, contrast sensitivity test, potential visual test, and specular microscopic of the cornea.

Treatment at Penn

Cataract Surgery

New surgical techniques allow doctors to remove a cataract at any stage in which a significant visual impairment is evident.

Removal of the Cataract

There are several ways to remove a cataract. The most commonly used method is the phacoemulsification technique where the cloudy lens is broken up, using an ultrasound probe that allows removal of the pieces through a tiny incision. A soft, plastic intraocular lens is then carefully inserted, and visual recovery is very rapid. The incision may not even require sutures.

The second, less commonly used technique, is extra capsular lens extraction. With the extra capsular technique, a larger incision is necessary, and the whole cataract is removed intact, rather than breaking it up with ultrasound. Visual rehabilitation takes somewhat longer than it does with the phacoemulsification method, because a larger incision is required. Most often, the phacoemulsification technique is used, but each technique has its advantages.

Penn Programs & Services for Cataracts

Cataracts Program

Learn about the ways we treat cataracts.

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