Laser thermokeratoplasty by means of a pulsed holmium:YAG laser for hyperopic correction.

A new technique of hyperopic correction similar to radial thermokeratoplasty is presented. A pulsed Holmium:YAG laser was used, emitting a wavelength of 2.06 microns. The laser light was guided by a quartz fiber and focused by means of a handpiece. Eight of 16 coagulations located on rings concentric to the pupil resulted in central corneal steepening. The refractive change increased with the applied pulse energy above a threshold of about 10 mJ per pulse and was constant between 15 and 35 mJ per pulse. The effect decreased linearly with greater distance from the center. Four blind human eyes demonstrated that the parameters evaluated in the human cadaver eyes can be transferred to the living eye. Immediately after surgery, folds in Descemet's membrane parallel to the limbus appeared. With time, they gradually diminished but were still persistent after 4 months. Hyperopic changes of up to 5.00 diopters were obtained, remaining stable for 4 months.