Corneal Morphometrics in Congenital Primary Aphakia: A Multimodal Imaging Perspective

Purpose: To characterize in vivo corneal architectural changes in congenital primary aphakia (CPA) using depth-resolved, layer-specific AS-OCT findings with those of age-matched controls. Methods: This observational study includes 31 eyes of 16 children with clinically diagnosed CPA. High-resolution AS-OCT was used to obtain meridional and lamellar corneal thickness measurements: anterior, central stromal, and posterior layers were quantified across 5 standard locations (central, nasal, temporal, superior, and inferior). Quadrant-wise and layer-wise values were compared within the CPA cohort and against 13 eyes of 7 age-matched controls. Statistical comparisons between groups and within the CPA group were performed using linear mixed-effects models with Bonferroni-adjusted pairwise comparisons. Results: CPA corneas demonstrated significant layer-wise thickness variations in both horizontal and vertical meridians (all P <0.001), driven predominantly by regional lamellar abnormalities. Central stromal layer thickness was markedly reduced in CPA group compared with controls (355 ± 22.7 vs.501 ± 33.6 μm; P = 0.001). In contrast, the anterior layer thickness paradoxically increased in several quadrants (central: 57.6 ± 6.6 vs. 32.9 ± 9.3 μm; P = 0.040), whereas the posterior layer was consistently and profoundly thick across all quadrants (central: 56.4 ± 9.1 vs. 15.5 ± 10.6 µm; P = 0.007). The total central corneal thickness was significantly lower in the CPA group than in the control group (433 ± 25.3 vs. 543 ± 38.3 µm; P = 0.023). Conclusions: CPA is associated with a unique, depth-specific corneal morphometric phenotype characterized by central stromal hypoplasia and thickening of anterior and posterior layers. These findings are likely because of the absence of embryonic lens impairing normal corneal morphogenesis. Layer-specific AS-OCT analysis refines CPA phenotype and supports clinical decision making.