Using the Simulated Cockpit to Validate Visual Performance After Photorefractive Keratectomy in USAF Personnel

摘要

In October 1998, the USAF endorsed a longitudinal clinical evaluation of the long-term effects of PRK on visual performance, including three cockpit simulation experiments. Twenty nonflying active duty AF personnel volunteered and were baselined before undergoing PRK at Wilford Hall Medical Center. All three experiments used adaptive threshold estimation to determine visual acuity (VA) and contrast sensitivity (CS) thresholds during various simulated cockpit tasks at baseline, 6-months, 12-months and 24-months post-PRK. Thresholds were determined using both a laser and broadband glare source and a no glare condition. Experiment 1 (Freiburg VA and CS) also used a windscreen experimental manipulation in half of the trial runs. Freiburg VA was almost two full Snellen lines worse with the laser glare source in place versus the broadband glare source, which may be due to masking from coherent spatial noise (laser speckle). Freiburg CS performance dropped significantly following PRK with the no glare condition only. PRK did not affect the ability of the subject to perform Experiment 2 & 3 flight tasks.