Comparative Histopathology of Cryosurgery and Photocoagulation

Abstract

With the development of the Linde-Cooper cryosurgical unit * and its modification by Drs. Lincoff, McLean, and Nano,¹ many of the technical difficulties of applying cold to the sclera have been overcome. This is not a new technique; in 1933 Bietti² and Deutschmann³ used carbon dioxide snow in a metal applicator to provide chorioretinal inflammatory lesions. The major advance in the Linde cryosurgical unit is the development of a vacuum insulated probe utilizing liquid nitrogen with an accurate temperature control. This permits rapid freezing and thawing of ocular tissues at controlled temperatures. In the past ten years, photocoagulation, which has been pioneered by Dr. Meyer-Schwickerath, has been shown to produce an effective chorioretinal adhesion.⁴ At the Bascom Palmer Eye Institute, the Zeiss photocoagulator has been used in more than 250 cases to seal retinal tears. In only one case did the retina subsequently detach at the site