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.