Comparative analysis of higher-order aberration profiles in macular and granular corneal dystrophies

To compare corneal topographic characteristics and higher-order aberration (HOA) profiles between macular corneal dystrophy (MCD) and granular corneal dystrophy (GCD) and to identify phenotype-specific structural determinants of optical degradation.

This cross-sectional comparative study included 81 eyes (49 MCD, 32 GCD) evaluated using Scheimpflug-Placido-based tomography. Corneal topographic parameters and wavefront-derived aberrations were analyzed over a 6-mm optical zone. Between-group comparisons were performed using the Mann-Whitney U test with false discovery rate correction. Spearman correlation and multivariable regression analyses were used to assess structural-optical associations.

Patients with GCD were older than those with MCD (p=0.006). MCD eyes demonstrated significantly greater astigmatism (p=0.001), lower corneal volume and central corneal thickness (both p<0.001), and steeper anterior mean keratometry (p<0.001). Total HOA burden was comparable between groups; however, GCD showed significantly higher spherical aberration (p<0.001) and posterior RMS values (p=0.001). Anterior Kmax demonstrated the strongest correlations with total RMS (ρ=0.66), total HOA (ρ=0.75), anterior RMS (ρ=0.67), and anterior HOA (ρ=0.73) (all p<0.01). Multivariable analysis identified anterior Kmax as the strongest independent predictor of multiple aberration parameters, while posterior aberrations showed phenotype-specific associations.

Although MCD and GCD exhibited similar overall HOA magnitude, they demonstrated distinct aberration profiles and structural-optical relationships. GCD was characterized by increased spherical and posterior aberrations, whereas MCD showed broader associations between structural abnormalities and optical degradation. Phenotype-specific HOA analysis may improve characterization of visual dysfunction and support more individualized management strategies.