Effects of aspirin and dimenhydrinate (Dramamine) on visual processes.

1. The effect of three doses of either aspirin (1280 mg each) or dimenhydrinate (Dramamine) (100 mg each) in an 8 h period on visual processes was investigated double-blind on sixteen volunteer subjects. 2. Tests included night-vision, colour-discrimination, stereoacuity and stereopsis, reaction-time, pupil size, eye-movements, visual evoked cortical potentials, electroencephalographs, a dial-reading task, and a test of texture discrimination. 3. Both drugs affected colour discrimination, and dimenhydrinate degraded night-vision, reaction-time, and stereopsis. 4. The effect of aspirin was minor, but the impairments produced by dimenhydrinate appear to be of practical importance.