On the safety of 193-nanometer excimer laser refractive corneal surgery

Current literature on the potential hazards of 193-nanometer excimer laser corneal surgery is reviewed. The healing process of the different layers involved in the procedure is examined. The epithelium regenerates without delay or abnormal adhesion. A certain loss of corneal transparency seems to be only a short-term complication. The phototoxic risk for the endothelium and the lens has not yet been fully investigated. This risk is presently thought to be minimal. Factors such as improper corneal centering could lead to degradation of best corrected visual acuity or to loss of contrast sensitivity. Results of the first clinical trials indicate that vision quality does not appear to be adversely affected. The last section reviews studies designed to investigate the mutagenicity and cytotoxicity of 193-nanometer UV radiation. In vivo experiments could find no evidence of cellular transformation.