Optical properties of 13 smoke-protective devices were determined. The devices tested comprised 8 goggles and 5 fullface oxygen masks (3 rigid one-piece masks and 2 flexible hoods). Those properties evaluated were: (i) light transmission, (ii) optical haze, (iii) prismatic deviation, (iv) refractive power, (v) optical distortion, and (vi) surface curvature. Data were compared with optical requirements formulated by USA Standard USAS Z 87.1 and Military Specification MIL-L-38169(USAF).
All clear transparencies met or exceeded standards for light transmission, and all but one (an experimental hood) met the standards for optical haze. All but 2 of 11 devices exceeded standards for spherical refractive power. Three fullface masks and two goggles with steep surface curvatures did not meet the optical requirements for prismatic deviation. Only 4 of 11 devices evaluated by a photographic method attained the standard for optical distortion; however, when the criterion of visible distortion was employed, as outlined in the military specification, 9 of the 11 devices conformed to the standard. Optical anomalies may be caused by facepiece configuration and surface curvature found in some of the smoke-protective devices.
This study was designed to determine the visual characteristics of smoke-protective devices for flight deck crews. Visual measurements were made on fi...
The Federal Air Surgeon requested continued investigation of visual disorders and vision corrective devices as to their relevance to the medical certi...
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