Effect of Flash Field Size on Flashblindness in an Aircraft Cockpit

Ten volunteers were exposed to high intensity double pulse light flashes with flash fields subtending 1, 3, 5, 10, and 15 degrees of visual angle. Flashblindness recovery times for several aircraft instruments were measured for each flash field diameter. Countermeasures including looking around the afterimage and body movement were permitted on some of the trials. Recovery time increased as the adapting flash visual angle was increased from 1 to 15 degrees. Instruments requiring a greater visual acuity to be read had substantially longer recovery times than instruments requiring less. The two countermeasures listed above were found to be helpful in reducing recovery time. Pub. in Aerospace Medicine, v42 n6 p630-634 Jun 1971.