Suchergebnisse

The time required to match a colored stimulus to one of a set of colors was measured as a function of color sets ranging in size from 2 to 10. Reaction time (RT) increased linearly with increases in set size to 5 or 6, after which the increase, although still linear, was less steep. Error rate increased sharply with set sizes of 8, 9, and 10. The relative RTs to the different colors remained constant despite changes in the experimental method.

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.

The visual performance using five commercially avaible facemasks was compared. Measurements were made of visual fields, visual acuity, stereoacuity, hand-eye coordination, accuracy of distance estimates, and accuracy of size estimates at both near and far distances. In addition, the optical properties of the masks were measured and the susceptibility of each mask to fogging was tested. There were significant differences among the masks for every visual process tested. Some masks were superior for one purpose and inferior for another purpose. For example, the mask which had lenses designed to compensate for the optical distortions found under water improved size and distance estimates and hand-eye coordination, but degraded acuity and stereoacuity. The results were not expplained on the basis of differential susceptibility to fogging.