A cataract is a cloudy area in the lens of the eye that blocks the normal passage of light through the eye.

Cataracts that begin in the center of the lens (nuclear cataracts) are the most common cause of worsening nearsightedness in adults. These cataracts are more common than the kind that begin to develop in the outer part of the lens.

Nearsightedness associated with cataracts in the center of the lens is often classified with the pseudomyopias, but it is actually a permanent change in the way light focuses in the eye. Cataract surgery corrects the myopia as well as the cataract.

The presence of pathological myopia may affect how cataracts are diagnosed and treated. It may be harder to tell whether nearsightedness is getting worse because of the cataracts or because of the progression of pathological myopia. People with pathological myopia who have cataract surgery are at higher risk for retinal detachment.

See a picture of an eye with cataracts.