1994 Volume 13 Issue 3-4 Pages 3-4_165-3-4_169
To obtain optimal retinal sections for routine histological evaluation of the monkey eye, 4 eyes were fixed in a 1.5% glutaraldehyde and 1% formaldehyde combined fixative about 30 minutes after the necropsy. Within 10 minutes after starting fixation, the fixative was injected into the vitreous, so that the contour of the globe was maintained. After 1 hour of fixation, by which time the eye became hard enough, it was sagittally cut in half with a razor blade to attain better fixation. The eye specimens were then placed in the fixative for 2 days. The retina was trimmed into ribbons including the optic disc and macula. The size of ribbons was limited to within 15×4 mm. They were embedded either in paraffin or glycol methacrylate (GMA), a water soluble resin (JB-4®, Polyscience Inc.). The paraffin and GMA blocks were cut at 3μm with a steel blade (S-35, Feather Safety Razor Co., Ltd.) and a special steel blade (H-35S, Feather Safety Razor Co., Ltd.), respectively. Retinal and choroidal artifacts such as folding, detachment and cracking which are often observed in formalin-fixed and paraffin-embedded sections were almost completely prevented by the fixation and embedding procedures described above. Fine architecture was better preserved in GMA specimens than in paraffin sections; particularly, the orientation of nerve fibers was clearly discernible in GMA specimens.
