In the study, supported in part by BrightFocus Foundation, researchers discovered a biological connection between darker pigmented eyes, which are known to be resistant to AMD, and increased levels of a chemical called L-DOPA in those eyes. Since L-DOPA is frequently prescribed for Parkinson's patients, the researchers wanted to know whether patients who received the drug L-DOPA as treatment for Parkinson's or other diseases were protected from AMD. By combing through massive databases of medical chart data, they reported that patients receiving L-DOPA were significantly less likely to get AMD, and when they did, its onset was significantly delayed.