Effects of Pterygium Surgery on Holladay Eqiuvalent Keratometry Readings

Aim: To investigate and compare the effects of pterygium surgery on the mean anterior surface Simulated Keratometry (SimK) and Holladay Equivalent Keratometry Readings-65 (EKR65) detail report. Methods: Patients who underwent pterygium surgery between August 2022 and January 2023 were examined. All surgeries were performed under local anesthesia with conjunctival autograft method. Pentacam topography was performed after detailed ophthalmological examination before and 3 months after surgery. The mean anterior SimK, EKR65 report results in all zones, mean anterior corneal radius (rfront) and mean posterior corneal radius (rback) parameters were investigated preoperatively and at 3 months. In addition, postoperative change amounts (Δ) of SimK and EKR65 data were calculated. Results: Twenty-four eyes of 24 patients were included in the study. The mean age of the patients was 51.50±9.48 (36-75) years. Mean anterior corneal surface SimK increased from 40.85±3.30 D, to 42.57±2.53 D at the postoperative 3rd month (p=0.003). The mean radius of curvature values on both anterior and posterior corneal surfaces decreased significantly (8.30±0.66 vs. 7.95±0.49, p=0.004, and 6.56±0.56 vs. 6.50±0.54, p=0.001, respectively). A general increase in EKR65 report values was observed in the postoperative period. Increases in EKR65 values at 4.5, 5, 6 and 7 mm were significant (p<0.05 for all). Both ΔEKR65 at 2mm and ΔEKR65 at 3mm were found to correlate with ΔSimK (r=0.371, p=0.044 and r=0.347, p= 0.046, respectively) Conclusion: Conventional keratometry calculations may be insufficient due to the irregularity of the cornea caused by pterygium surgery. The EKR65 report may be more prominent in these corneas.