Abstract
Purpose:
To develop a chronic ocular hypertension model in the African green monkeys, and to investigate the glaucomatous injury to the neuroretina and optic nerve in this model, which shares a lamina cribrosa, macula and other neuroanatomic characteristics unique to humans and nonhuman primates.
Methods:
The trabecular meshwork in one eye of each monkey received a single session of laser photocoagulation. Slit-lamp biomicroscopy, tonometry, optical coherence tomography (OCT) and fundus photography were used to monitor changes in intraocular pressure (IOP), anterior chamber inflammation, retinal nerve fiber layer (RNFL) and ganglion cell layer (GCL) thickness, and optic disc morphology. Photomicrographs of histology were obtained and observations qualitatively and quantitatively correlated to OCT findings. All work was conducted in compliance with the ARVO Statement for the Use of Animals in Ophthalmic and Vision Research.
Results:
A single session of laser photocoagulation on the trabecular meshwork induced an elevation of IOP ≥45 mmHg in 67% of eyes starting at one week post-laser and was sustained throughout the 8-week observation period, indicating the chronic ocular hypertension model is reproducible in African Green monkeys. Sustained IOP elevation resulted in glaucomatous changes in the neuroretina and ONH, including reduction of RNFL, expansion of the ONH cupping, thinning of the neuroretinal rim and displacement of the blood vessels emerging from the disc. Those glaucomatous changes are similar to that observed in human optic discs with glaucoma-induced atrophy, suggesting a high homology of the chronic ocular hypertension model with the human disease.
Conclusions:
Sustained IOP elevation achieved by laser ablation and subsequent scarification of the trabecular meshwork can be employed as a chronic ocular hypertension model in African green monkeys and used for testing neuro-protection compounds in translational studies.
Keywords: 610 nerve fiber layer •
615 neuroprotection •
578 laser