The United Kingdom’s Defence Science and Technology Laboratory (Dstl) conducted assessments of six modified off-the-shelf prototype laser eye protection (LEP) devices designed to protect dismounted soldiers against known laser threats. The prototypes were all dye-based and relatively low cost. The assessments included: 1) measurements of optical properties with comparisons to standards and requirements, 2) laboratory evaluations of the LEP’s effect on contrast sensitivity and colour vision, and 3) a field trial that examined the effect of four prototypes on militarily relevant target detection/recognition/identification tasks and the participant’s ability to navigate a small-scale navigation course under low ambient light (i.e. scotopic to low mesoptic) conditions.
The field trial included 12 military member participants with a variety of experience levels. It was conducted in a controlled environment that permitted the precise control of environmental lighting. In general, the prototypes exhibited good optical quality that met standards and protection requirements. All six prototypes showed decreased contrast sensitivity and colour discrimination relative to the clear ballistic eye protection condition that served as a baseline. For the navigation course, a within-subjects ANOVA showed significant main effects for ambient light level (F = 12.642, p = 0.006) and LEP type (F = 7.665, p = 0.001). There was also a statistically significant correlation between the integrated visual photopic transmission of the prototype and the overall acceptability rating reported by participants (r = 0.648, p < 0.001 for the lowest, 30 mlux ambient light level). The results of this study will inform United Kingdom Ministry of Defence procurements of LEP that provide appropriate laser protection while also allowing wearers to function in low light environments.
Crown copyright (2020), Dstl. This material is licensed under the terms of the Open Government Licence (http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3).