Increase in rabbit corneal curvature by heated ring application.

This study demonstrated that increases of corneal curvature in living rabbits could be induced through the application of heated brass rings. The peak increase averaged 10.5 D in a series of 19 eyes, as compared to the nontreated fellow eyes. This change tended to be transient, was not prolonged with the use of steroids locally, and tended to return to normal within two to three weeks. The mechanism of this change involved the creation of a rigid desiccated pseudo-limbus holding the cornea in the configuration of increased curvature. With the rehydration of the desiccated area, the cornea then reassumes its pretreated curvature and configuration. The application of the rings heated to about 98C produced a very low incidence of corneal ulceration. Further experiments showed that burn ulceration is a temperature-dependent phenomenon rarely found with application of heat less than 110C.