Optic nerve axon count and axon diameter in patients with ocular hypertension and normal visual fields

Abstract

Background: At postmortem examination, the authors obtained eight eyes of five individuals with elevated intraocular pressure and normal visual fields to study the axon count and mean axon diameter.

Methods: Automated image analysis was used to calculate the total axon count and mean axon diameter per nerve and per nerve segment for each eye. The authors applied the method of identification analysis to compare each study eye with a corresponding normal eye of patients of the same age.

Results: There was no statistically significant difference compared with control subjects for total axon count or segmental axon count for any of the eyes. Two eyes showed a statistically significant difference for mean axon diameter for the whole nerve but not for individual segments of the nerve.

Conclusions: Some eyes subjected to varying duration and magnitude of intraocular pressure elevation with normal visual fields may maintain normal axon counts and mean axon diameters.