Correlations of pterygial blood flow with corneal refractive properties and higher-order aberrations: A cross-sectional OCTA study.

PURPOSE: To evaluate the associations between pterygial blood flow density (BFD) and corneal refractive properties, including higher-order aberrations (HOAs).

METHODS

This cross-sectional study enrolled 41 patients with primary unilateral pterygium. Anterior segment OCTA was utilized to measure blood flow density in the limbal regions of the pterygium, while the Pentacam HR system was used to assess corneal refractive parameters. Associations between regional blood flow density and corneal parameters were subsequently evaluated using correlation analysis.

RESULTS

Central BFD (45.66±8.64%) was significantly lower compared to superior (49.88±4.55%, p < 0.001) and inferior regions (48.61±6.94%, p = 0.02). Furthermore, central BFD correlated significantly with mean keratometry (Km) (r=-0.36, p = 0.02) and astigmatism (r = 0.42, p = 0.01). It also showed significant positive correlations with total HOAs and total 4th order aberrations across the anterior, posterior, and total cornea (correlation coefficients 0.33 to 0.59, all p'<0.05). Notably, total HOAs and 4th order aberrations of posterior surface exhibited the strongest correlations (correlation coefficient 0.54 to 0.56, p'<0.001).

CONCLUSION

Pterygium exhibit a distinct spatial blood flow perfusion pattern, characterized by significantly lower BFD in the central region compared to the periphery. This localized hypoperfusion correlates closely with altered corneal refractive properties and optical degradation, positioning central BFD as a critical biomarker for the severity of corneal refractive changes. Moreover, central BFD exhibits a robust correlation with HOAs, which is most pronounced on the posterior corneal surface. Consequently, dynamic HOA metrics serve as sensitive potential indicators for monitoring the relationship between pterygium vascularisation and corneal optical status.