Discovery of clinical manifestations in spontaneous glaucoma suspect non-human primates.

INTRODUCTION: The primary aim of this study was to assess the longitudinal changes in RNFL thickness and relative ONH parameters using spectral-domain optical coherence tomography (SD-OCT) in living eyes of non-human primates with spontaneous glaucoma.

METHODS: Totally 9 macaque subjects underwent a standard fundus photo and OCT examination, including 3 adult monkeys with stable elevated intraocular pressure (IOP) as the glaucoma suspect group, and 6 normal IOP monkeys as the control group. Each eye of primates with IOP measurement was repeated three times. OCT measurements recorded retinal nerve fiber layer thickness (RNFL), Bruch's membrane opening (BMO) minimum rim width (MRW). The follow-up scan of glaucomatous subjects was underwent in 10 months.

RESULTS: The mean ages of glaucoma and healthy subjects are 19.33 ± 0.33 and 20.5 ± 1.46 years. Elevated IOP was achieved in three non-human primate eyes with an average increase of 10 mm Hg over the study period. Elevated IOP was associated with decreased RNFL thickness in all the regions, and decreased RNFL phase retardation in the superior and inferior regions. When averaged over the entire retinal area, only the whole RNFL and temporal regions showed a significant decrease. The mean IPL thicknesses are 87.17 ± 2.15μm in glaucomatous and 93.33 ± 1.51μm in healthy eyes (P = 0.03). Lamina cribrosa parameters are measured from the OCT images and showed significant differences between glaucoma primates and normal primates.

CONCLUSIONS: Of the measured parameters, decreased RNFL and MRW were correlated with glaucomatous damage. Natural glaucoma primate can be a natural glaucoma model which is closer to glaucoma in humans.