Drug may delay, prevent blindness for millions of older Americans

http://www.eurekalert.org/pub_releases/2015-11/lsb-sdm110915.php

Public Release: 9-Nov-2015
Study: Drug may delay, prevent blindness for millions of older Americans
Lindsay, Ston & Briggs

A drug already used safely to treat Parkinson's disease, restless leg syndrome and other movement disorders also could delay or prevent the most common cause of blindness affecting more than 9 million older Americans - age-related macular degeneration (AMD).

Researchers have discovered that patients who take the drug L-DOPA are significantly less likely to develop AMD, and if they do get AMD it's at a significantly older age, according to the study published online Nov. 4 in the American Journal of Medicine. The retrospective study was led by researchers at Marshfield Clinic Research Foundation, University of Arizona, Medical College of Wisconsin, University of Miami, Essentia Health, Stanford University and University of Southern California.

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AMD, the No. 1 cause of legal blindness in adults over 60, is a progressive eye condition affecting as many as one in three adults. The disease attacks the macula of the eye, where the sharpest central vision occurs, causing central blindness. This vision is used to drive, read, recognize faces and perform daily tasks. AMD spares the peripheral vision, leaving dim images or black holes at the center of vision.

L-DOPA is a natural by-product of pigmentation and is made in a layer of cells in the back of the eye that functions to promote health and survival of retinal tissues. Researchers asked the question if people taking L-DOPA as a medicine are protected from AMD.

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Race and ocular pigmentation are known risk factors for developing AMD, indicating darker pigmentation may protect from the disease as it occurs much, much more frequently in the white population than black or Hispanic populations.

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"This study suggests an intriguing link between patients taking L-DOPA and a lower incidence and delayed onset of AMD," said Paul A. Sieving, M.D., Ph.D., director of the National Eye Institute. "Showing that L-DOPA causes this protective effect will require further investigation, but if confirmed, could lead to new drugs or combination therapies for AMD that target DOPA-responsive cells in the retina."

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