Patterns of optic nerve head and retinal nerve fiber layer damage in the monkey chronic ocular hypertension model

Abstract

Objective To investigate if the chronic ocular hypertension (COHT) in a monkey model presents indistinguishable from humans in its retinal nerve fiber layer (RNFL) and optic nerve head (ONH) damage.Methods This was an experimental study.Models of COHT were induced in 12 eyes of rhesus monkeys were induced by using VISULAS Trion to disturb the aqueous humor outflow and cause the elevation of intraocular pressure.Some measurements have been taken such as intraocular pressure (IOP),fundus photography,the ONH parameters,and the RNFL thickness were taken every week before and after laser treatment.Results The main results were as follows:the IOP of the twelve eyes of the monkeys was 16.08±2.02 mmHg,the central corneal thickness was 489.17±17.82 μm and the ocular axials length was 20.32±0.84 mm.Eleven eyes,underwent 3 to 4 laser photocoagulation treatments,were induced to the COHT model.The average IOP in 27 weeks was 30.32±14.59 mmHg,and the variation was 8.19±7.45 mmHg.Optical coherence tomography displayed revealed the a lost rim area that changed from 1.67±0.44 mm2 to 0.43±0.34 mm2 in the monkey COHT model.The RNFL was changed from 97.92±6.79 μm to 64.46±17.44 μm.Conclusion The monkey COHT model mimicks the natural ocular hypertension/open angle glaucoma procedure and shares similar glaucomatous damage patterns,such as the reactivity of ONH to ocular hypertension,and the presence of the optic cup and the damage phenomenon of RNFL.The monkey model is an ideal animal model for studying damage of the optic nerve head and RNFL. Key words: Rhesus monkey; Animal model; Ocular hypertension; Retinal nerve fiber layer