Eyes / Eye Diseases

Macular Degeneration: When Cataracts are also Present

When a patient with macular degeneration also has a cataract, a special situation exists. A cataract is a cloudiness of the natural lens inside the eye which can cause significant vision loss. Of course, macular degeneration causes vision loss as well. Removing the cataract will only restore that amount of vision that was blurred by the cataract. Cataract surgery will not restore vision lost by macular degeneration.

This leaves the physician and patient with a dilemma. Will removing the cataract improve the vision enough to be worthwhile? The answer to this problem is another question: How much of the vision loss is due to cataract, and how much to macular degeneration?

A simple test, called the potential acuity test, can be done to help answer these questions. Using a potential acuity meter (or PAM), an eye chart can be shown directly into the eye. The patient then reads the smallest visible letters. The PAM is able to bypass the cataract, so any improvement in vision is a simulation of the vision one can expect if the cataract was removed. It is not an exact measurement nor a guarantee, but it does give an idea of whether or not removing the cataract will help improve the vision.