Visual Acuity with and without Binoculars through Thick Observation Tower Windows

摘要

Daytime visual acuity with and without hand-held M-19 7x50 binoculars was tested inside and outside of the cab of a Master Surveillance Control Facility (MSCF) Tower at Eglin AFB outfitted laminated transparent armor windows. There windows were tested, one with 13 observers and two with 5 observers. High, medium, and low contrast tri-bar resolution charts were used 400 feet from the base of the tower. Observers selected the smallest resolvable resolution pattern. The purpose was to determine if the windows were causing an appreciable loss in visual acuity. Differences between observers were large. Statistical tests found no significant loss in acuity, with or without binoculars, at any test chart contrast . The three windows were not signigicantly different in optical quality. Visual acuity with the binoculars averaged 4.5 to 6 times better than unaided eye acuity. It is concluded that the windows examined, and similiar ones, cause negligible loss in visual acuity with hand-held binoculars. Optical quality of the windows is adequate for observers.