Longitudinal Changes in Choroidal Thickness Across the Eye in Young Children With Premyopia.

BACKGROUND

The choroid is thought to be implicated in eye growth regulation, yet longitudinal choroidal data in young children are limited.

METHODS

Choroidal thickness (ChT) was measured in 92 children with functional emmetropia (baseline age, 7.4 ± 0.8 years; cycloplegic refractive error, +1.01 ± 0.55 diopters) enrolled in the 3-year PICNIC (Preventing Myopia: Investigating Contributing Factors to Nearsightedness in Children) study. Wide-field spectral domain OCT radial scans (12-line, enhanced depth imaging) were segmented using a neural network and sampled at annular eccentricities (1, 3, 6, 10, and 14 mm) in four quadrants (temporal, superior, nasal, and inferior). A generalized linear mixed model evaluated the effects of risk group (low risk vs. high risk, based on baseline hyperopic reserve and parental myopia), eccentricity, quadrant, visit, axial length (AXL), and age. A separate linear mixed model was used to assess the preonset ChT in children who developed myopia.

RESULTS

After adjustment for age and AXL, ChT decreased with eccentricity and varied by quadrant (P < 0.001). ChT increased across visits (P < 0.001), whereas greater AXL was independently associated with a thinner ChT (P < 0.001). No main effect of risk group was observed (P > 0.20); however, a significant Risk group × Eccentricity × Quadrant interaction (P < 0.001) indicated distinct spatial profiles with low-risk children, who exhibited thicker choroids, whereas children at high risk showed steeper thinning. In the preonset analysis, the mean ChT did not differ between future myopes and persistent nonmyopes (P = 0.16), but a significant Myopia status × Eccentricity interaction (P < 0.01) indicated thinner choroids before onset.

CONCLUSIONS

Choroidal remodeling in early childhood is spatially patterned. Although the global ChT did not differ by risk group, altered spatial profiles were evident in high-risk children and future myopes before clinical onset. These results support a potential role for wide-field spatial metrics in the identification of early structural susceptibility to myopia.