Incision Gape and Its Correlation with Surgically Induced Astigmatism in Subconjunctival Oblique Limbus Incision Cataract Surgery

Abstract

Purpose To investigate the phenomenon of incision gape following subconjunctival oblique limbus incision (SCOLI) cataract surgery and to quantify its relationship with surgically induced astigmatism (SIA). Methods This study enrolled patients with regular corneal astigmatism ≥1.0 diopters (D) undergoing SCOLI. Anterior segment optical coherence tomography (AS-OCT) was used to measure the actual incision gape (ΔG). A theoretical model was developed to calculate the predicted incision gape (theoretical ΔG) based on preoperative keratometry and white-to-white (WTW) distance. The correlation between actual ΔG and SIA was analyzed using linear regression and a multivariate GEE model. Results Thirty-two eyes of 25 patients were analyzed. A significant positive correlation was observed between actual ΔG and SIA (R = 0.392, p = 0.026). In the multivariate GEE model, after adjusting for age (p = 0.195) and CCT (p = 0.070), actual ΔG remained a significant independent factor associated with SIA (B = 0.004; 95% CI, 0.002–0.006; p < 0.001). The theoretical ΔG showed a strong correlation with both the intraoperative ΔG (r = 0.877, p < 0.001) and the actual ΔG (r = 0.508, p = 0.003). Conclusion A macroscopic incision gape is a prevalent phenomenon in SCOLI and is a significant factor associated with SIA. The developed mathematical model provides a foundation for predicting astigmatic outcomes, highlighting the potential for controlling SIA by surgically modulating the incision gape (ΔG).