The scotopic threshold of the human retina during static physical effort

The scotopic threshold of 15 subjects was measured with a 1 degree circular white stimulus light placed at 15 degrees below the fixation level during 45 min at rest followed by 20 min constant pedalling on an ergometric bicycle with the head stationary. Loads were adjusted individually so that the effort extended by each subject required 60-75% of his maximum oxygen uptake. Similar results were obtained under both resting and effort conditions, indicating that the dark adaptation threshold remained unaffected by vigorous static effort.