Normative OCT-derived ocular measurements in rhesus macaques

To define normative OCT-derived measurements of the retina, optic nerve head (ONH) macrostructure, and lamina cribrosa (LC) microstructure in a large cohort of healthy, predominantly youngadult rhesus macaques, and to investigate their association with demographic traits and image quality. In vivo spectral-domain OCT (SD-OCT) scans of the macula, peripapillary retina, and ONH were obtained from 52 healthy animals (90 eyes). Macular and peripapillary scans were segmented to measure the retinal nerve fiber layer (RNFL), ganglion cell-inner plexiform layer (GCIPL), and total retinal thicknesses. ONH macrostructure and LC microstructure were quantified using software of our own design. Linear mixed-effects modeling was used to assess association between demographic features, image quality, and OCT-derived ocular measurements. Average macular GCIPL and peripapillary RNFL thicknesses were 80.6 ± 6.4 and 96.8 ± 8.9 µm, respectively. Average cup-to-disc ratio and cup depth were 0.46 ± 0.18 and 75.6 ± 50.3 µm, respectively. Average LC beam-to-pore-ratio was 2.06 ± 0.37. Significant associations existed between LC OCT quality and most LC microstructural parameters. We present robust normative ocular measurements of the healthy rhesus macaque eye and demonstrate LC microstructural measurements are sensitive to image quality, which should be considered in any future analysis of these parameters.