Minami K, et al. - Researchers assessed the changes in corneal higher-order aberrations induced by advancement of pterygium using an anterior-segment optical coherence tomography (AS-OCT) and Zernike aberration analysis. Pterygium size was reflected by the increase in higher-order aberrations, and significant aberrations were induced in 5.0 mm diameter when the end exceeded 25% of the corneal diameter. objective grading of pterygium advancement based on changes in corneal optics could be enabled by the use of AS-OCT and Zernike analysis.