Return of Vision and Other Observations in Replanted Amphibian Eyes.

Abstract

Since Koppanyi 1 reported that vision returned in certain vertebrate eyes after replantation and transplantation, conflicting results have been published which show that return of vision as well as other related problems is still unsettled. Technique in operation and handling of the replanted or transplanted eyes has much to do with its subsequent conditions. In such problems it is of value to know the existing conditions in both young and adult animals. We are pursuing the problem with this in mind.

Operations on Amblystoma punctatum larvae (19 to 23 mm.) and adult Diemyctylus viridescens are here reported. Chloretone anesthetic was used. The eyes were excised by finely sharpened iredectomy scissors and forceps manipulated under the compound dissecting microscope. Very little hemorrhage was encountered.

Return of circulation was first noted within superficial vessels in the iris, in Amblystoma larvae as early as 24 hours after operation, in Diemyctylus as early as the 5th day. Resorption of the eye could usually be predicted by known injuries to the bulb at the time of operation, or by too long use of anesthetic or a too strong anesthetic. Slight reduction in the size of the eye after operation always persisted in Diemyctylus, the maximum reduction being attained in about a month. In Amblystoma larvae reduction did not always take place. When it did there was usually rapid recovery. The cornea occasionally became opaque, but in most cases became clear about the time of observed return of circulation. All specimens of both types of amphibians kept several months after operation showed corneal reflex, when only the cornea was touched by a fine hair. In many Diemyctylus, 7 weeks after operation replanted eyes readily retracted when the cornea was so stimulated.