Facilitating the transition from bright to dim environments

Abstract

High on the list of desired capabilities for warfighters noted at the 2008 Fort Benning “Lab Day” was the development of combat protective eyewear with lenses that would instantly change the amount of light they transmit, based on incident lighting conditions. We reviewed the investigation regarding the effect of four different protective spectacle lens designs [clear, standard sunglass, step filter (SF), and electro-optical (EO)] on a soldier’s ability to rapidly transition from bright to dim environments. The dependent measures were selected to specifically permit the findings to be evaluated in both clinical and operational terms. A multifactorial analysis of variance revealed global statistically significant interactive effects regarding the viewing lenses, subject marksmanship, and subject visual acuity. The subjective preference ratings indicated a clear preference for the SF and the EO eyewear over no eyewear, the Authorized Protective Eyewear List (APEL) clear eyewear, and the APEL sun eyewear. Operational performance results while wearing either of these two optical devices (the SF eyewear and the electronic eyewear) are equally effective. Consequently, the fielding of either transition strategy provides equal acceptance and utility by the soldiers using this transitional gear.