| Popis: |
Background: Laser illumination of aircraft continues to constitute a problem in national and international air traffic, requiring effective protection measures for pilots and accompanying personnel. The protective glasses used by the German Air Force to date, do not meet current requirements in terms of visual demands and extent of protection, especially for military pilots. The present study addresses the visual and operational testing of a contemporary laser protection eyewear for flying personnel, developed in cooperation with industry. Methods: Based on the optophysical properties of commercially available laser protection glasses, a combined dye and coating process was developed allowing simultaneous blocking of laser irradiation at different wavelengths in visible and invisible ranges of the light spectrum. The referring filters were modified until the desired attenuation was achieved and the first prototype could be provided. Compatibility with visual requirements for flying personnel was verified at the German Air Force Centre of Aerospace Medicine; testing included visual acuity, color discrimination, contrast sensitivity, and subjective visual comfort. Glasses were developed by ESG Inc., Fuerstenfeldbruck, with involvement of test pilots from the Bundeswehr Test Facility 61 in Manching, mission pilots from Fritzlar, and under expert supervision of the Federal Office of Bundeswehr Equipment, Information Technology and In-Service Support (BAAINBw) in Koblenz. Results: Simultaneous blocking of three wavelengths in RGB mode resulted in acceptable visual acuity values while largely maintaining color discrimination in all 3 color spaces. The relative change in AQ values was 14–15 % in the deuteranomal and 10–38 % in the protanomal range, depending on transmission and protection level. The probability of error in color discrimination was 4–9 % under photopic and 19–32 % under mesopic conditions. In contrast to selective attenuation in conventional devices, this resulted in a saturation loss of about 30 % and a contrast reduction of about 25 %. Additive blocking of UV-A, UV-B and Near-Infrared did not introduce any effect on visual acuity and color vision of tested study subjects. Discussion and conclusions: Our results show that it is technically possible to design laser safety eyewear that provides effective protection in three visible and three invisible wavelength bands without compromising visual perception and color vision relevant to flight safety. Increasing color saturation and contrast sensitivity will be subject to further research, along with increasing levels of protection. The prototype developed here is expected to be available for distribution from the third quarter of 2022, following final testing by WTD 64 and operational approval by BAAINBw. |
