Age changes in the Wistar albino rat eye.

Over 200 rat eyes were enucleated for this study. The youngest rats were 21 days and the oldest 1,000 days old. All specimens were removed with as little trauma as possible and trimmed of adventitial tissue with small scissors and for­ ceps. Measurements were made with a small caliper having a micrometer adjust­ ment before the eyes were completely fixed, with the exception of the 1,000-day group which were measured after fixation. Rela­ tive weights were thought to be insufficiently conclusive because of inability to remove all of the episcleral tissue, muscle, and so forth. Histologic sections were prepared by standard techniques and resulting slides were divided into four groups for each age category. Group A was prepared for study by stain­ ing with standard hematoxylin and eosin and the specimens were examined specifically for morphologic changes. Group B was prepared by staining with a modification of the Masson trichome tech­ nique and the specimens were examined particularly for changes in connective-tissue structures and degenerative processes. Group C was prepared by the technique of McManus-Hotchkiss (Day, Friedenwald, Hotchkiss). This is a chemical procedure by