Diopter Focus of ANVIS Eyepieces Using Monocular and Binocular Techniques
Abstract
U.S. Army aviators were asked to obtain best resolution using an ophthalmic phoropter with three different focusing techniques, viewing with unaided vision and through the aviator's night vision imaging system (ANVIS). Eight participants were over 40 years old and 16 participants were less than 30 years old. The method labeled 'Clearest' vision allowed the participant to oscillate the diopter lens powers to obtain best resolution in both positive (correction for hyperopia, and to reduce accommodation) and negative (correction for myopia, and to stimulate accommodation) lens power directions, monocularly. The 'Maximum Plus' method instructed the participants to first blur the tri-bar target using excessive plus lens power to go past infinity and then change the lens powers towards the minus values just to clearest vision and no further using monocular vision. The 'Binocular technique involved blurring both eyes slightly with excessive plus lens power and then instructing the participant to reduce the plus lens power for one eye to clearest vision binocularly. The procedures were repeated with the other eye. The results showed that the 'Binocular' focusing technique for best resolution induced less negative lens powers than the 'Maximum Plus' and 'Clearest' vision methods both with and without the ANVIS. The difference in the lens power between unaided and ANVIS best resolution focusing values was approximately -0.25 diopter with the ANVIS.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 2002
- Accession Number
- ADA400108
Entities
People
- Crina Van De Pol
- William E. McLean
Organizations
- United States Army Aeromedical Research Lab