Effects of Altitude Exposure in Photorefractive Keratectomy (PRK) Subjects

http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA521192&Location=U2&doc=GetTRDoc.pdf


AFRL-SA-BR-TR-2010-0003

Tutt, R.C., Ivan, D.J., Baldwin, J.B., Hiers, P.L., O’Connor, R.
Dooley, J.W.; Smith, R.E., LoRusso, F.J. and Thompson, W.T


Purpose: To assess the effects of unpressurized altitude on visual acuity, refractive error, and corneal stability measures, pre- and post- PRK treatment. Methods: Sixteen male and four female subjects volunteered for altitude training and data collection. Two separate unpressurized altitude profiles were undertaken by all subjects; a 12-hour 10,000-ft (10K) and a 20-min 35,000-ft (35K) simulated altitude flights. Baseline "ground level" visual acuity, refractive error, and corneal stability data were collected prior to each profile. These measures were repeated "in-flight" at 3, 7, and 10 hours for the 10K profile and at peak altitude for the 35K profile. The test profiles were re-accomplished approximately 6 months after a subject’s PRK treatment date. Results: No significant differences attributed to altitude exposure were found in measurements of pre- or post-PRK visual acuity, refractive error, or corneal stability, under either unpressurized altitude profile. Conclusions: Visual acuity, refractive error, and corneal stability data were not significantly affected by exposure to unpressurized altitude within the design of this study. Comprehensive study data results and analysis are presented.