# Age-Related Regional Changes in Choroidal Vascularity in Healthy Emmetropic Eyes

## TL;DR

This study shows how the blood vessel density in the choroid changes with age in healthy eyes, revealing regional differences that could help understand eye diseases.

## Contribution

The study identifies age-related regional changes in choroidal vascularity in healthy emmetropic eyes using deep learning methods.

## Key findings

- The choroidal vascularity index (CVI) decreases significantly from childhood to adulthood.
- CVI increases from the fovea toward the perifovea and from the temporal to the nasal hemiretina.
- Age-related CVI decline is driven by nasal stromal thickening and temporal luminal thinning.

## Abstract

This retrospective cross-sectional study examined regional changes in choroidal vascularity index (CVI) with physiological aging in healthy emmetropes.

Deep learning methods were used for segmentation and binarization of enhanced depth imaging optical coherence tomography images of the choroid collected from 280 healthy emmetropic subjects (mean spherical equivalent refraction: +0.39 ± 0.38 D), including 83 children (5–12 years), 77 adolescents (13–17 years), and 120 adults (18–41 years). The CVI, calculated as the ratio of luminal versus total choroidal area (in percent), and luminal and stromal choroidal thickness were measured across the 5-mm horizontal macular region centered on the fovea. Linear mixed models were used to examine age-related regional changes in the choroid while controlling for gender and imaging time of day.

The macular CVI reduced significantly from childhood (65% ± 0.5%) and adolescence (63% ± 0.5%) to adulthood (59% ± 0.4%) (P < 0.001). Significant regional variations were observed (P < 0.001) with the CVI increasing from the fovea (61% ± 0.3%) toward the perifovea (64% ± 0.3%) and from the temporal (61.4% ± 0.3%) toward the nasal hemiretina (63% ± 0.3%). The age-related decrease in the CVI was greater in the nasal (−7% ± 0.7%) than the temporal (−6% ± 0.7%) macula (P = 0.014) and was associated with a significant nasal stromal thickening (45 ± 5 µm; P < 0.001) and temporal luminal thinning (−16 ± 6 µm; P = 0.033) from childhood to adulthood.

Physiological aging was associated with a significant region-dependent decline in the CVI driven, primarily by stromal thickening in the nasal and luminal thinning in the temporal macula.

These age-related changes in the CVI provide new insights into the physiological morphology of the choroid during aging and may aid clinicians in understanding the spatial and age-associated predilections of certain chorioretinal diseases.