REGENERATION TIMES-Reply

Abstract

To the Editor. —My apologies for not presenting the material on regeneration times more clearly. Dr. Weale is quite right in pointing out that the time for total regeneration is not comparable to the time for 50% regeneration. A careful reading of the review will indicate that no attempt was made to compare such values. Rather, the observations for both half and total regeneration are used to support the idea that an 11-cis retinal precursor may be present in the outer segments. If this hypothetical reservoir is exhausted or depleted, then migration to the pigment epithelium for isomerization is probably required, and a relatively long time can be expected for total regeneration. However, where only a small section of the retina has been bleached, it can be argued that the precursors present in the area surrounding the bleached zone may rapidly move in. Thus, the regeneration time may be dependent