Establishment of the ocular hypertension model using the common marmoset

The purpose of this study was to establish an experimental glaucoma model in the common marmoset (Callithrix jacchus). Chronic intraocular pressure (IOP) elevation was induced by laser trabeculoplasty twice at 2-week intervals in the left eyes of 4 common marmosets. IOP was measured before and at 4, 7, 8, 11, 13 weeks after first laser treatment, and ophthalmoscopic examinations were also performed. At 13 weeks after laser treatment, each eye was enucleated, and retinal cross-sections and optic nerve were prepared for histological examination. Mean IOP values measured at the above 5 time points were over 40 mmHg in laser-treated eyes in 3 marmosets, but IOP in one marmoset was transiently increased to 26.6 mmHg at 7 weeks and then declined to the baseline level. In ophthalmoscopy, deepened and enlarged optic disc cupping, depending on the extent of IOP elevation and duration, were observed in laser-treated eyes of 3 marmosets with persistent IOP elevation, but there was no apparent change in the optic disc in the laser-treated eye of one marmoset with transient IOP elevation. Histological examination showed marked atrophy with deepened and enlarged cupping of optic disc, thinning of retinal nerve fiber layer and retinal ganglion loss in the retina, and axonal atrophy and loss in the optic nerve, depending on the extent of IOP elevation and duration. In conclusion, we succeeded in producing an experimental glaucoma model in the common marmoset, and this model may be useful in elucidating the pathophysiological mechanism for glaucoma.