The influence of pterygium size on corneal refractive properties and higher-order aberrations.

OBJECTIVE

To evaluate associations between pterygium size parameters and corneal refractive properties and higher-order aberrations (HOAs).

METHODS

In 41 patients with unilateral pterygium, thickness, length, and width were measured by anterior segment optical coherence tomography(AS-OCT). Corneal refractive parameters, irregularity indices, and HOAs were assessed using Pentacam HR. Correlation analyses evaluated relationships between pterygium dimensions and corneal parameters.

RESULTS

Pterygium length and width significantly correlated with multiple corneal parameters in the 3-7 mm zone. Moderate correlations were found with K1 (length: |r| = 0.376-0.473; width: |r| = 0.361-0.415; all p < 0.05), and stronger correlations with corneal astigmatism (length: r = 0.582-0.642; width: r = 0.529-0.581; all p < 0.001) and irregularity indices (ISV, IVA, IHD) (length: r = 0.623-0.637; width: r = 0.566-0.596; all p < 0.001). Length positively correlated with total, third-, and fourth-order HOA RMS across the anterior and posterior surface, and entire cornea (r = 0.455-0.691, p < 0.05), primarily driven by vertical trefoil, vertical coma, and tetrafoil. Width also correlated with anterior and total corneal HOAs (r = 0.519 to 0.645, p < 0.05). Posterior surface correlations for width were weaker (r = 0.313 to 0.472, p < 0.05) but remained significant for total RMS, third-order RMS, and several specific aberrations.

CONCLUSION

Pterygium length and width are key parameters associated with deteriorated corneal refractive status, irregularity, and HOAs. Width, being easily standardized, serves as a practical indicator for predicting pterygium-induced visual quality deterioration.