Aircraft pilots used to use an eye patch, or close one eye to preserve night vision when there was disparity in the light intensity within or outside their aircraft, such as when flying at night over brightly lit cities, so that one eye could look out, and the other would be adjusted for the dim lighting of the cockpit to read unlit instruments and maps.[9] The FAA still recommends, “a pilot should close one eye when using a light to preserve some degree of night vision”.[10] Some military pilots have worn a lead-lined or gold-lined eyepatch, to protect against blindness in both eyes, in the event of a nuclear blast or laser weapon attack.[11][12][13]

Eyepatches are not currently used by military personnel; modern technology has provided an array of other means to preserve and enhance night vision, including red-light and low-level white lights, and night vision devices.[14][15][16]