Astigmatic Thermokeratoplasty Using C W Lasers

The research is for the evaluation of hyperopic and astigmatic thermokeratoplasty using a newlyavailable continuous wave (cw) laser as an alternative to pulsed lasers. The hypothesis to be testedis that continuous wave infrared laser radiation can produce controlled heat shrinkage of collagen fibersin the cornea for correction of refractive errors, with greater long term predictability than pulsed laserssuch as the Ho:YAG. The new infrared laser will be tuned to wavelength allowing delivery ofnon-coagulating heat to stromal tissue, while minimizing heating of Bowman's and Descemet's layersand the corneal endothelium. A modulated delivery system will deliver power in a ring-shaped patternto correct hyperopic refractive errors, or vary power delivery to selected areas of the corneal to correctastigmatism. Preliminary experiments in this laboratory indicate that myopic correction may also beachieved. Experiments in live animals will determine long-term beneficial and adverse effects. The longterm objective of this research plan is the development of a compact commercial laser device providinga low risk alternative to radial keratotomy and photo refractive keratotomy by avoiding scarring orirregularity of the optical zone.