Comparative Analysis of Retinal and Choroidal Vascular Parameters in Healthy Rhesus Monkeys of Different Age Groups.

BACKGROUND: Non-human primates are essential models in basic vision research due to their retinal structure and function being closely comparable to those of humans. Systematic Optical Coherence Tomography Angiography (OCTA) studies on retinal and choroidal vessels in rhesus monkeys of different ages will enhance our understanding of the underlying pathology of human retinal vascular diseases and offer valuable insights for preclinical translational research. METHODS: Data were collected from 26 rhesus monkeys, categorized into infant, juvenile, adult, and geriatric groups based on age. OCTA measured vascular density (VD) in the superficial, deep, and inner retinal layers, as well as choroidal vascular density, using 1×1 mm, 3×3 mm, and 6×6 mm scans of the macular area. A one-way analysis of variance (ANOVA) with LSD post hoc tests was used for statistical analysis. RESULTS: Significant age-related differences in VD were observed across all rhesus macaque groups in the three retinal layers and the choroid. In the superficial retina, the maximum VD values across all groups were observed in the 3-6 mm region. In all groups, the highest VD values for both the deep and inner retinal layers were observed in the 1-3 mm region. Furthermore, VD values across all retinal layers increased in the juvenile group compared with the infant group, whereas they decreased in the elderly group compared with the adult group. Results for the choroidal VD in the central region indicated that VD values across all groups were highest at 1-3 mm. The trend of age-related changes in choroidal VD corresponds with that of retinal VD. CONCLUSIONS: Superficial VD peaks at 3-6 mm, while deep, inner, and choroidal VD all reach their maximum at 1-3 mm. These values typically peak during adolescence and gradually decline with age.