Abstract
Purpose :
Non-human primate (NHP) experimental models have improved understanding of pathophysiological changes in ocular disorders, including glaucoma and myopia. However, there is a lack of data directly comparing optic nerve head (ONH) structure between healthy male and female NHPs. We sought to determine whether sex-based differences exist in in vivo measures of ONH parameters of healthy NHP eyes
Methods :
We conducted a retrospective analysis of spectral domain optical coherence tomography (SDOCT) images (12 and 48-line 20° radial B-scans, 20°x20° volume scans; Spectralis HRA+OCT) centered on the ONH and acquired in one healthy/control eye of 25 male (age range: 3.0 - 13.6 years) and 20 female (age range: 3.2 - 13.9 years) rhesus macaques. Ocular biometry measurements were incorporated into a three-surface schematic eye and used to laterally scale SDOCT images. Scans were imported into a custom MATLAB program that automatically segmented ONH features (including the Inner Limiting Membrane, Bruch’s Membrane termination points, and anterior/posterior lamina cribrosa surfaces) using a neural network. Global minimum rim width (MRW), Bruch’s membrane opening (BMO) height, BMO area, anterior lamina cribrosa surface (ALCS) depth, ALCS thickness, and retinal nerve fiber layer (RNFL) thickness at 550 µm from the best-fitting BMO ellipse were calculated. An independent t-test or Mann-Whitney U test was used to compare parameters between males and females.
Results :
Age was not significantly different between male and female NHPs (mean ± st. dev. = 6.7 ± 3.1 years vs. 7.4 ± 3.3 years, respectively; P=0.45). Male eyes were significantly longer than female eyes (mean ± st. dev. = 19.3 ± 1.1 mm vs. 18.5 ± 0.8 mm, respectively; P<0.01). However, there were no associations between axial length and ONH parameters in male or female eyes. While males tended to have slightly thicker RNFLs compared to females (mean ± st. dev. = 131.6 ± 9.1 µm vs. 126.7 ± 9.4 µm, respectively; P=0.08), no ONH parameters were significantly different between male and female eyes (P>0.05).
Conclusions :
While no sex-based differences in ONH morphology were observed in this cohort of NHP eyes, future studies could assess whether sex-based differences exist in biomechanical or physiological responses to changes in the ocular environment for different models of ocular disorders.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.