Psychophysical Test of Contrast Acuity to Aid Operational Effectiveness of Aircrew Laser Eye Protection (LEP)
Abstract
Four experiments were conducted to gain insights for evaluating LEP and to better understand the basis of cone inputs to contrast acuity. In Experiment 1, a set of five tests were evaluated on paper, LCD, and CRT media. Three tests (Regan letters, bar gratings, and Landolt octagons) were selected for further study with motion in Experiment 2. The two best tests (Regan letters and bar gratings) were selected for further study with ND filters in Experiment 3. The same two tests were again studied with spectrally selective filters in Experiment 4. In addition to recommending Regan letters and bar gratings (also perhaps Landolt octagons) for the evaluation of LEP, two important lessons learned were 1) the importance of using low contrast stimuli and 2) the high acuity obtainable with LCD displays. The data from the two filter studies were well fit with a simple equation based on transmittance and contrast. The ND filter data can be used as a benchmark for LEP evaluation and the spectral filtering suggests that the importance of m-cone input has been underemphasired in acuity.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 2005
- Accession Number
- ADA438158
Entities
People
- Jim Dykes
Organizations
- University of Texas at San Antonio