3D choroidal vascularity index in hyperopic amblyopic eyes of preschool children: a case-control study using SS-OCTA

To evaluate the three-dimensional choroidal vascularity index (3D-CVI) in amblyopic eyes of preschool children compared with age-matched healthy controls using swept-source optical coherence tomography angiography (SS-OCTA).

A cross-sectional case-control study was conducted. Children aged between 4y and less than 7y diagnosed with hyperopic amblyopia were consecutively recruited between January 1, 2021 and May 30, 2024. Age-matched controls were selected from healthy children without ocular or systemic diseases. All participants underwent SS-OCTA scanning, and choroidal parameters-including 3D-CVI, choroidal vessel volume (CVV), and choroidal thickness (CT)-were analyzed in both foveal and parafoveal regions. Comparative and correlational analyses were conducted to examine differences between groups and to explore the relationship between best-corrected visual acuity (BCVA) and 3D-CVI.

A total of 80 eyes (40 amblyopic and 40 age-matched controls) were included. 3D-CVI was significantly lower in the amblyopic group compared to controls in both the foveal [0.318 (0.2885-0.3525) vs 0.381 (0.3460-0.4212), P<0.05] and parafoveal [0.331 (0.2982-0.3589) vs 0.386 (0.3538-0.4293), P<0.05] regions. Similarly, CT was significantly higher in the amblyopic group than in the control group in both the foveal (438±67.3 vs 369±74.1 µm, P<0.001) and parafoveal regions (419±59.0 vs 353±67.5 µm, P<0.001), whereas CVV did not differ significantly between the two groups in either region (P>0.05). Furthermore, multivariate regression analysis showed that BCVA was positively associated with foveal 3D-CVI (P=0.024), whereas no such association was found in the parafoveal region.

Hyperopic amblyopic eyes in preschool children show significantly lower foveal and parafoveal 3D-CVI compared to normal controls, suggesting a potential reduction in 3D-CVI during early refractive development. Lower foveal 3D-CVI is also associated with poorer BCVA, suggesting that 3D-CVI may serve as a valuable parameter for monitoring structural changes in hyperopic amblyopia.