AIM: To explore the factors associated with significant corneal astigmatism during the perioperative period in patients with pterygium. METHODS: Patients with primary pterygium presenting at Shanxi Eye Hospital between February and June 2025 were enrolled. All patients underwent medical history collection. Pre- and postoperative data were obtained using Pentacam, anterior segment photography, Image J software, and anterior segment optical coherence tomography(AS-OCT). All patients underwent pterygium excision combined with autologous bulbar conjunctival flap transplantation under local infiltration anesthesia. RESULTS: A total of 76 patients(76 eyes)with pterygium were finally enrolled(30 males, 46 females)with a mean age of 62.2±8.2 y. The mean length of corneal invasion by pterygium was 3.61±0.89 mm, the mean depth of invasion into the anterior corneal surface was 0.15±0.09 mm, and the median area of corneal invasion was 10.25(6.90, 18.75)mm2. The median preoperative corneal astigmatism was 1.50(0.70, 5.45)D. Median astigmatism was 0.8(0.40, 1.28)D at 2 wk postoperatively and 0.60(0.30, 1.15)D at 1 mo postoperatively. Patient age showed a positive correlation with preoperative astigmatism, and with residual astigmatism at 2 wk and 1 mo postoperatively(all P<0.05). The length of corneal invasion was positively correlated with preoperative astigmatism and residual astigmatism at both postoperative timepoints(P<0.01). The depth of invasion showed no significant linear correlation with astigmatism at any stage(P=0.250, 0.761, 0.686). The area of corneal invasion was positively correlated with astigmatism at all stages(P<0.01). Patients were grouped based on significant astigmatism(≥1.0 D)and non-significant astigmatism(<1.0 D), after adjusting for other variables, age(P=0.031)and the area of corneal invasion(P=0.004)were identified as risk factors for significant astigmatism. Pterygium invasion length was not significant factors(P>0.05). Receiver operating characteristic(ROC)analysis showed the highest area under the curve(AUC)for the invasion area(AUC=0.915). CONCLUSION: Significant preoperative corneal astigmatism in pterygium patients is correlated with patient age, the length of corneal invasion, and the area of invasion. The area of pterygium invasion into the cornea is the strongest predictor of significant preoperative corneal astigmatism.