A previously developed 193-nm excimer laser system, the ExciMed UV200LA, will be used to perform photorefractive keratectomy using two different treatment techniques. The clinical results of the ExciMed W200LA with an electronically driven iris aperture delivery system will be compared to an ExciMed UV200LA with a fixed-beam diameter used in conjunction with an ablatable mask. Development of the ablatable mask will be carried out, and a range of operating parameters for performing photorefractive keratectomy with the ablatable mask will be determined in material models, in vitro and in vivo. Analysis of the data collected in rabbits and monkeys will determine if the ablatable mask technique will be used in further human clinical trials of photorefractive keratectomy.Awardee's statement ofthe potential commercial applications of the research: This program would determine which of two techniques for performing photorefractive keratectomy will yield better results. Photorefractive keratectomy could potentially benefit a large number of the 137 million people in the United States with refractive disorders and would therefore be expected to have major commercial applications.National Eye Institute (NEI)
