Experimental Cyclocryothermy in Rabbits

ABSTRACT

The effects of Cryosurgery of the ciliary body on the aqueous humor dynamics of ten albino rabbits were studied by perfusion experiments. The cryo-probe (tip diameter, 3 mm) was frozen by dry ice and alcohol mixture and applied over the full circumference of the eye 2 mm from the limbus for 30 seconds. Eight applications were made in each eye. Intraocular pressure fell during the first 10 days after surgery, the amount of fall averaged 2.5 mmHg (12.6% of the pre-treatment level). Thereafter the intraocular pressure rose gradually in all eyes and reached almost to the original level 3 weeks after surgery. Facility of outflow changed inconsistently, showing no definite pattern. Aqueous flow showed significant reductions during the 2 to 3 weeks after treatment, then gradually recovered. There was no significant reduction in flow after the end of 3 weeks. No complications were encountered except mild iridocyclitis during the first week. The unsatisfactory outcome of this cryotherapy is considered to be due to the insufficient freezing of the ciliary body, and more applications is recommended in order to produce more sustained reduction of intraocular pressure.