OPTIC-NERVE AXON COUNT AND AXON DIAMETER IN PATIENTS WITH OCULAR HYPERTENSION AND NORMAL VISUAL-FIELDS

Background: At postmortem examination, the authors obtained eight eyes of five individuals with elevated intraocular pressure and normal vis ual fields to study the axon count and mean axon diameter. Methods: Au tomated image analysis was used to calculate the total axon count and mean axon diameter per nerve and per nerve segment for each eye. The a uthors applied the method of identification analysis to compare each s tudy eye with a corresponding normal eye of patients of the same age. Results: There was no statistically significant difference compared wi th control subjects for total axon count or segmental axon count for a ny of the eyes. Two eyes showed a statistically significant difference for mean axon diameter for the whole nerve but not for individual seg ments of the nerve. Conclusions: Some eyes subjected to varying durati on and magnitude of intraocular pressure elevation with normal visual fields may maintain normal axon counts and mean axon diameters.