DISTRIBUTION OF AXONAL-TRANSPORT BLOCKADE BY ACUTE INTRAOCULAR-PRESSURE ELEVATION IN PRIMATE OPTIC-NERVE HEAD

Abstract

The degree of axonal transport blockade was studied in various areas of the optic nerve head with acute intraocular pressure (IOP) elevation in 19 squirrel monkey [Saimiri sciureus] eyes. When IOP was raised to 20-50 mm Hg for 7 h, mild axonal transport blockade occurred in each area of the disk, most prominently in nerve fiber bundles of the superior pole. With 7 h IOP elevations between 50-90 mm Hg, a somewhat greater degree of transport blockade occurred throughout the nerve head, although again the superior and inferior poles were somewhat more affected. The distribution of short-term transport blockade over the entire nerve head corresponded to the diffuse damage of acute glaucoma, but the pattern hints at the preference for damage near the poles of the disk seen in chronic glaucoma. Before these results can be fully evaluated, further information is needed on axonal pathways through the optic nerve head and on the relationship between transport obstruction and ganglion cell death.