Grafting of Larval and Adult Eyes in Amblystoma Punctatum

Abstract

Replanted and transplanted eyes of Amblystoma punctatum were studied daily for many months in 193 larval grafts on larval hosts around 21 mm. in length and in 102 adult grafts on adult hosts varying in age from 1 to 2 years and in length from 6 to 18 cm. Since no striking differences exist based merely on replantation and transplantation, a comparison is given based on the age of the graft. Return of circulation after operation was obtained in 40% of old adults, where sloughing or partial resorption was high, against 80% of young adults. Its earliest appearance was on the first day in young adults and on the third day in old adults. The earliest in larvae was 18 hours. Although in adults it had occurred earlier in the younger specimens than in older ones it was present in half of the cases in 10 days. By the fourth day it was observed in one-half of the larvae. About one-third of adult grafts and most of the larval eyes showed no corneal or lenticular opacity. In a few cases of adult and larval grafts the opacity was transient but in any case of excessive trauma sloughing of the bulb was subsequent to a corneal change. In the black pigmented iris of adult grafts changes were dependent upon early return of circulation. When they took place a subcorneal hemorrhage involving a segment of the iris appeared during the first 2 weeks. If limited in area regeneration was complete within a month in which a new capillary network was formed. If extensive, but not involving sloughing, it was accompanied by a delay in retinal regeneration. In the yellow pigmented larval eye a slight temporary dulling of the luster of the iris sometimes occurred during the first 2 or 3 weeks. A slight postoperative reduction in the size of adult and larval grafts is usually found during degenerative changes in the retina. In the growing larval eye it is more marked until circulation returns and by the twentieth day a size equal to that of the normal control is usually obtained. In adult grafts the size reduction is usually permanently established by about a month as in Triturus or slightly longer depending upon the age of the host and the amount of degeneration. In adult grafts miosis was noted in some cases immediately after operation—a condition which persisted only about a week. In larval grafts immediately after operation miosis was observed in some and mydriasis in others, but the condition lasted only a few days. In many the pupil did not change. The pupillary reflex persisted uninterruptedly until death at 57 days in one young adult transplant. Usually the pupillary reflex was interrupted during the first week. This was followed by a recovery within 2 to 4 weeks. A few young adults showed an immediate postoperative absence of pupillary response lasting over several weeks before recovery. In larval grafts the pupillary reflex always occurred at metamorphosis and continued uninterruptedly.,