Effect of the Neutral Density Helmet Visor on the Visual Acuity of Navy Fighter Pilots

摘要

The visual acuity of 63 Navy fighter pilots was measured under four viewing conditions in an Automated Vision Test Battery housed in a Mobile Field Laboratory operated by the Naval Aerospace Medical Research Laboratory (NAMRL). These and other pilots were also interviewed concerning their visor usage habits. Use of the 12% neutral density visor resulted in an average acuity loss of about 0.51 minutes of visual angle (mva) for low contrast targets under high-luminance laboratory conditions. The visor may cause and operationally significant reduction in visual acuity in the presence of luminance levels encountered at typical flight altitudes. Pilots range widely in their sensitivities to reduced contrast and glare, so a single optical density visor would not be optimal for many pilots. Pilot attempts to identify individually-optimal strategies for using visors and sunglasses often have no objective or systematic basis. Recommendations are presented for improving the vision of aviators wearing visors.