IMPAIRED COLOR-VISION IN COCAINE-WITHDRAWN PATIENTS

Background: The main reinforcing effect of cocaine happens by altering dopaminergic neurotransmission in the brain reward systems. Dopamine is found in high concentrations in the retina in which it plays an imp ortant role in color vision. Therefore, we investigated whether cocain e-dependent patients might have impaired color vision. Methods: We com pared patients recently withdrawn from cocaine (n=31) with matched nor mal controls (n=31) on 2 color vision tests. Results: Cocaine-withdraw n patients had significantly higher error scores than matched controls on the Farnsworth-Munsell 100-hue and Lanthony desaturated D-15 color vision tests. Also, 23 of the 31 cocaine-withdrawn patients had blue- yellow color vision losses on the Farnsworth-Munsell 100-hue test comp ared with 3 controls (P<.001, chi(2) test) and 15 had blue-yellow colo r vision loss on the Lanthony desaturated D-15 test compared with 2 co ntrols (P<.001, chi(2) test). Conclusions: These significantly higher test error scores and blue-yellow color vision losses suggest that col or vision is impaired in cocaine-withdrawn patients. Color vision test ing may be useful in future studies of cocaine-dependent patients.