Retinal and Choriocapillaris Thickness and Age in Macaques in Development and Aging.

Total retinal thickness and multiple inner retinal layer thicknesses were positively associated with age before age 4 years in cynomolgus macaques, then negatively associated after age 4 years.

• OCT images were obtained from 543 eyes from 285 macaques aged 0.78 to 22.4 years
• Piecewise linear mixed effects models were used to examine associations between age and layer thicknesses
• Age 4 years in macaques was noted as equivalent to approximately 12 years in humans
• Layers showing this biphasic pattern included total retinal thickness, ganglion cell layer, inner nuclear layer, and parafoveal outer nuclear layer thickness

Retinal nerve fiber layer and foveal outer nuclear layer thickness were negatively associated with age throughout the entire age range in cynomolgus macaques.

• This negative association was observed across the full age range of 0.78 to 22.4 years
• Unlike other retinal layers, these layers did not show a developmental thickening phase
• Analysis used piecewise linear mixed effects models on 543 eyes from 285 macaques

RPE/Bruch's membrane and choriocapillaris layer thicknesses were positively associated with age throughout the entire age range in cynomolgus macaques.

• This positive association with age was observed across the full age range studied (0.78 to 22.4 years)
• The pattern was opposite to that seen in most retinal layers, which showed thinning in the adult/aging phase
• Piecewise linear mixed effects models were used for analysis

Choriocapillaris diameter was positively correlated with age in postmortem human specimens.

• Choriocapillaris thickness was assessed microscopically in postmortem human globes from 24 individuals
• Human subjects ranged in age from 11 to 82 years
• This finding in humans corroborated the choriocapillaris thickening pattern observed in cynomolgus macaques
• The authors interpreted this increase as suggesting aging-related remodeling of the choriocapillaris

Cynomolgus macaques were validated as a valuable nonhuman primate model for studying both developmental and aging-related retinal and subretinal changes.

• The study examined 543 eyes from 285 macaques spanning a wide age range of 0.78 to 22.4 years
• The macaque developmental retinal changes (thickening through juvenile stage) and aging changes (subsequent thinning) parallel known human retinal development and aging patterns
• Agreement between macaque choriocapillaris changes and human postmortem findings supports translational relevance of the model
• The authors noted that age 4 years in cynomolgus macaques corresponds to approximately 12 years in humans