Acute effects of alcohol on saccadic eye movements

Four components of 20 degrees horizontal saccadic eye movements, i.e., latency, mean and maximum velocities, and duration were measured in 16 students under the influence of alcohol and also in a control situation. The experimental procedures were standardized and automated as much as possible. Latency (simple eye reaction time) was not influenced by alcohol in blood concentrations of 0.056--0.116%. Mean and maximum eye velocities decreased by about 9% and duration of saccades increased by 11%. The maximum changes occurred 90--120 min after the start of alcohol ingestion. The changes in velocities and durations correlated more closely with feelings of intoxication than with blood alcohol concentrations. There were great intra- and intersubject variations in reactions to alcohol. The close resemblance between the effects of certain psychotropic drugs, alcohol, fatigue, and decreased attention on eye movement control suggest that all these may act upon the same nervous structures in the brain stem.