Comparison of Corneal Irregularity After Recurrent and Primary Pterygium Surgery Using Fourier Harmonic Analysis.

Purpose To the best of our knowledge, few detailed investigation of astigmatism with recurrent pterygium currently exists. We aimed to evaluate corneal irregularity after recurrent pterygium surgery. Methods This observational study included consecutive patients who underwent recurrent pterygium surgery and were observed for >12 months postoperatively via corneal examination. Patients who underwent primary pterygium surgery during the same period served as controls. Pterygium size and corneal irregularity evaluated with Fourier harmonic analysis (spherical component, regular astigmatism, asymmetry component, and higher-order irregularity) were compared between groups preoperatively and at 1, 3, 6, and 12 months postoperatively. Results Overall, 203 eyes of 203 patients (age, 66.5 ± 9.5 years) were included, of which 44 eyes had recurrent pterygium and 159 had primary pterygium. Regular astigmatism in the recurrent pterygium group was higher than that in the primary pterygium group preoperatively and at 1 and 3 months postoperatively. The asymmetry component and higher-order irregularity in the recurrent pterygium group were higher than those in the primary pterygium group at all observation points. Conclusions Fourier harmonic analysis showed that larger corneal irregularity that could not be corrected with spectacles persisted for a long time after recurrent pterygium excision than after primary pterygium excision. Thus, recurrence prevention is critical for primary pterygium surgery. Translational relevance We demonstrated that larger corneal irregularity that could not be corrected with spectacles remained long after excision of recurrent pterygium compared with excision of primary pterygium; thus, the prevention of recurrence is clinically important for primary pterygium surgery in terms of corneal irregularity.