The Effect of Vibration on Visual Acuity with Electro-Optical Aids to Night Vision1

Visual acuity at a level of illumination comparable to overcast starlight was measured at various frequencies and amplitudes of vibration chosen to be representative of conditions aboard various ships. Measures were made with electro-optical scopes of four-power and one-power, standard Navy 7×50 binoculars, four-power field glasses, and the naked eye. Decrements in acuity under vibration were largest for the four-power scope and least for the naked eye. The decrements were, in fact, directly related to the original acuity level determined for the specific optical systems with no vibration. Despite the loss, vision with the four-power electro-optical aid remained superior to that with any other system under all conditions. The importance of antivibration mounts is emphasized.