Regional difference in fenestration of choroidal capillaries in Japanese monkey eye

The fenestration of the endothelial cells of the choroidal capillaries in the periphery, posterior pole and macular region of the eyeball was studied comparatively by the freeze-fracture technique and morphometric analysis. Fenestrations in the P face appeared as circular or ovoid, vallate papillae, whereas those in the E face appeared as craters. The central know of the diaphragm, which is composed of a cluster of particles, could be observed in some fenestrations. The average diameter of fenestrations was 95.5 +/- 9.9 nm in the periphy, 73.2 +/- 4.8 nm in the posterior pole and 79.3 +/- 4.5 nm in the macular region. Among these three areas, the difference in diameter of fenestrations was significant (P less than 0.01). The average number of fenestrations per 1 micron2 was 32.0 +/- 4.4 in the periphery 39.3 +/- 2.5 in the posterior pole and 45.0 +/- 2.6 in the macular region. The difference in the density of fenestrations was significant (P less than 0.01) between the periphery and the macular region. The regional difference in the density of fenestration may indicate the functional difference of the relating retinal portion.