The eye, the only organ normally exposed in subzero climates, shows a remarkable tolerance to severely low temperatures. In the development of new approaches to the treatment of various ocular diseases, cryotherapy has taken advantage of this resistance to cold. Low-temperature techniques have now been applied to the treatment of cataracts (cryoextraction), retinal detachment (cryopexy), glaucoma ( cryocyclotherapy ), and dendritic keratitis, as well as to obliterate vascular lesions of the eye. In 1961, Krwawicz1 first reported the technique of cryogenic cataract extraction. This provided an impetus for American ophthalmologists to develop new and improved instruments, using various cryogens, and quickly established the value and superiority of cryoextraction over older methods.
Cryoextraction provides better control and maneuverability in cataract removal, since there is no sounder mechanical principle for grasping the lens than the intralenticular fusion provided by superfreezing. This procedure distributes the tractive force over the entire lens, so that the