Ophthalmic applications of infrared lasers -- thermal considerations

An analysis of the thermal response of clear ocular media to infrared laser radiation is presented. It is shown that from a thermodynamic viewpoint, it should be feasible to use infrared lasers in both vitrectomy and thermokeratoplasty. In vitrectomy, temperature elevations from vitreous vaporization with an intraocular CO2 laser probe would be well below retinal damage threshold levels at distances greater than 2 mm from the center of the beam. In thermokeratoplasty, peak temperature elevations could be moved from the corneal epithelium back into the corneal stroma where collagen shrinkage is desired. Other potential applications for infrared lasers are presented, and the value of accurate measurement of the infrared optical properties of ocular media is emphasized.