Unresolved issues in excimer laser corneal surgery

More than one hundred fifty clinical excimer laser units designed for corneal surgery have been developed and sold commercially. Manufacturers include Meditec Lasers in Germany, Summit Engineering, Taunton Technologies, and Visx in the United States, and Synthelabo in France. Furthermore a number of prototypes have been built in the USSR and other countries which are being investigated for their clinical use. While in the United States and Canada, substantial regulation of these devices has limited their distribution and use, sales in other parts of the world have been restricted only by market forces. Early clinical successes have created an enthusiasm for this new technology. In spite of this, substantial technical issues remain uncertain and have not been carefully studied. Indeed we have accepted certain parameters for on an almost serendipitous, empirical basis. It is a proper time to pause and consider the bases for these laser techniques.