Comparison of lens regeneration in adult newts, Triturus viridescens, between light and dark preadapted and non-preadapted animals.

It is well known that if the original lens is removed from the eyeball in certain Urodeles, a new lens will regenerate from the dorsal iris. Experiments were designed to study the different effects on lens regeneration in the newt, Triturus viridescens, between the light and dark preadapted animals and light and dark non-preadapted animals. The preadapted animals were preadapted to continuous light or dark for 90 days prior to lentectomy. The newts remained in the same controlled environments postlentectomy for 25 days to test the effect of light preadaptation on lens regeneration. The non-preadapted animals were placed in the light controlled environment immediately after lentectomy for a 25-day regeneration period. The results indicated that there was no difference in the rate of regeneration between continuous light preadapted and non preadapted animals. However, the dark non-preadapted animals regenerated new lenses at a much slower rate than the dark preadapted animals. The rate of lens regeneration was similar among the controls with 12 hours of light per 24-hour period, the dark preadapted, the continuous light preadapted, and continuous light non-preadapted groups.