Controlled lens formation with unapertured excimer lasers: use with organic polymers and corneal tissues.

A theoretical model is developed which allows for well-defined lenses to be formed with different dioptric properties using lasers that are known to ablate a variety of materials. With the theoretical development as a guide an experimental arrangement is defined for the ArF excimer laser and this arrangement is used to form lenses with highly smooth surfaces in three polymeric materials (polymethyl methacrylate, polycarbonate, and polyvinyl chloride) to test the validity of the theory. As part of the procedure to obtain these lenses, ablation curves (etch depth per pulse vs log of the laser fluence) were measured for each of these polymers and these curves are also reported. The experiments were extended to the rabbit cornea in which the corneal button was reshaped as part of keratomileusis surgery. This preliminary experiment resulted in a clear cornea with a smooth corneal surface and a measured change of 3 diopters in the treated eye.