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Cataracts

Description

An in-depth report on the causes, diagnosis, treatment, and prevention of cataracts.

Symptoms

During the early stages, cataracts have little effect on vision. The symptoms of a cataract may include:

• Cloudy vision, double vision, or both may be the first signs.
• Images may take on a yellowish tint as color vibrancy diminishes.
• Reading may become difficult over time because of a reduced contrast between letters and their background.
• Sensitivity to bright lights may make it difficult or impossible to drive at night because of glare from the headlights of oncoming cars. (People with diffuse cataracts in the rear walls of their lenses are particularly prone to glare sensitivity because bright light tends to scatter in their lenses.)
• In very advanced cases, the pupil, which is normally black, looks milky or yellowish. The patient's vision is reduced to being able only to distinguish light from dark.

Symptoms in Specific Locations

Nuclear Cataracts. Cataracts of the lens nucleus are most commonly associated with aging. Symptoms include:

• Hazy distance vision and increasing glare.
• Progressive nearsightedness and the need for frequent changes in eyeglass prescriptions. This effect may even temporarily counteract age-related farsightedness and provide a temporary improvement in overall vision in some people. The improvement fades when the cataract advances sufficiently to overwhelm the inherent farsightedness. Eventually, as the cataracts grow worse, stronger glasses can no longer correct the patient's vision.

Cortical Cataracts. Cortical cataracts usually start on the outside of the cortex (the outer area of the lens).

• They have very little initial effect on vision.
• Glare can develop as these cataracts increase and approach the center of the lens.
• Problems with distance vision, contrast sensitivity, and clarity may occur as the cataracts progress further.

Posterior Subcapsular Cataracts. Posterior subcapsular cataracts typically start near the center of the back part of the capsule surrounding the lens. These cataracts often advance rapidly. For many patients, major impairment of eyesight, including near-vision problems and glare, develops within several months.

• Review Date: 3/1/2007
• Reviewed By: Harvey Simon, MD, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital

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