# Association between fundus tessellated density and subfoveal choroidal thickness in children with different refractive statuses

## TL;DR

This study finds a nonlinear link between fundus tessellated density and choroidal thickness in children with myopia, suggesting a potential non-invasive biomarker for tracking myopia progression.

## Contribution

The study introduces a novel AI-based method to quantify fundus tessellated density as a potential biomarker for monitoring myopia progression in children.

## Key findings

- Fundus tessellated density increases as subfoveal choroidal thickness decreases in myopic children.
- A nonlinear threshold effect was identified when choroidal thickness dropped below 148.90 μm.
- Combined assessment of fundus tessellated density and choroidal thickness may improve early detection of myopia progression.

## Abstract

Present study aimed to quantitatively evaluate the association between fundus tessellated density (FTD) and subfoveal choroidal thickness (SFCT) in children with different refractive statuses and to explore the potential of FTD as a non-invasive biomarker for monitoring myopic progression.

A cross-sectional study was conducted involving 619 eyes of 315 children aged 6–12 years. Participants were classified into four refractive groups: hyperopia, pre-myopia, low myopia, and moderate-to-high myopia. FTD was quantitatively assessed using artificial intelligence (AI)-based analysis of color fundus photographs. SFCT and central subfield thickness (CST) were measured using swept-source optical coherence tomography (SS-OCT). Correlation and threshold effect analyses were performed to examine the relationship between FTD and SFCT.

SFCT decreased significantly with increasing myopic severity (p < 0.001), while FTD showed a corresponding increase (p < 0.001). A significant negative correlation was observed between FTD and SFCT in pre-myopia (r = −0.183, p = 0.019), low myopia (r = −0.335, p < 0.001), and moderate-to-high myopia (r = −0.222, p = 0.008) groups, but not in hyperopia (p = 0.454). A nonlinear threshold effect was identified: when SFCT decreased below 148.90 μm in the overall cohort, FTD increased markedly, suggesting that this value may serve as a potential reference point for myopia management. This threshold decreased with higher myopic severity. CST did not follow a linear gradient with refraction but was increased in moderate-to-high myopia.

FTD and SFCT are significantly associated in a nonlinear manner in myopic children, with a defined threshold effect that varies by refractive status. AI-based FTD measurement offers a reproducible and accessible method for quantifying early structural changes in myopia. The identified nonlinear relationship and threshold suggest that combined assessment of FTD and SFCT may hold promise for improving early detection and monitoring of pediatric myopic progression, warranting further longitudinal validation.