Return of Vision in Transplanted Adult Salamander Eyes After Several Days of Refrigeration. ∗

It has been shown that adult salamander eyes can be transplanted successfully if they are grafted immediately after enucleation. 1 , 2 Return of vision 4 times in the same eye repeatedly transplanted demonstrates 3 how successful the results can be. The capacity of an adult salamander eye to recover is tested further in the following experiments by isolating it from its blood supply for a long period.

Fifty-nine enucleated adult Triturus viridescens eyes were refrigerated from 0°C to 8°C in sterile Ringer's solution for periods varying from 2 to 14 days and then transplanted into freshly denuded orbits of new hosts. Under freezing conditions (0°C) the eyes were usually imbedded in solid ice in a little over an hour after they were placed in the refrigerator. The grafts exposed to the lowest temperature were first thawed in cool (10°C) Ringer's solution before transplantation. After 4 days these eyes are usually clear but the iris sinks inward with the pupil relaxed and distorted. By 7 and 8 days the cornea may be either slightly or densely opaque. In some cases, protions of the cornea, along with degenerating iris cells, begin to slough. The lens usually becomes opaque and degenerated, and by this time only rarely is it still clear. All of the graftwed eyes which had been frozen showed little powere for recovery. They sloughed or were rapidly were merely small white sacs.

When the eyes were maintained at a higher temperature (8° C) in the ice box better results were obtained. At the end of 2 days at this temperature the eyes appeared about the same as at the time of excision. A few eyes transplanted at this time recovered and showed return of vision by the third month. Compared with eyes grafted immediately after excision recovery was slower in the survivals. The degeneration stages seemed to take place earlier and were so extensive, in some cases, that by the second month they were resorbed.