A Impact of Incision Size on Astigmatism: A Comparative Evaluation of 2.8 mm and 2.2 mm in Phacoemulsification

Background: Modern cataract surgery aims not only to restore vision but also to achieve optimal refractive outcomes. Surgically induced astigmatism (SIA), influenced by incision size, remains a key factor affecting postoperative visual quality. This study compares the magnitude of SIA following phacoemulsification performed through 2.8 mm (standard) versus 2.2 mm (microincision) clear corneal incisions.Methods: This prospective, interventional, comparative study included 100 eyes of 100 patients undergoing uneventful phacoemulsification at a tertiary eye care center. Patients were randomly assigned into two groups: Group 1 (2.8 mm incision) and Group 2 (2.2 mm incision), each comprising 50 eyes. Pre- and postoperative keratometric readings were obtained using an automated keratometer. SIA was calculated using the Holladay-Cravy-Koch vector analysis via Dr. Hill’s SIA calculator. The primary outcome was mean SIA at one-month postoperatively. Secondary outcomes included visual acuity and distribution of SIA subgroups. Statistical analysis was performed using Student’s t-test, with significance defined as p < 0.05.Results: At one-month follow-up, both groups demonstrated favorable visual outcomes, with 96% of patients in Group 1 and 98% in Group 2 achieving best-corrected visual acuity between 6/6 and 6/18. The mean SIA was 0.9594 ± 0.32 D in the 2.8 mm group and 0.9434 ± 0.28 D in the 2.2 mm group (p = 0.9313), indicating no statistically significant difference. However, a greater proportion of patients in the 2.2 mm group exhibited SIA <0.5 D (40% vs. 36%), and fewer had SIA >2.0 D (12% vs. 16%).Conclusion: Although the 2.2 mm microincision technique demonstrated a trend toward lower surgically induced astigmatism, the difference compared to the 2.8 mm incision was not statistically significant. Both incision sizes produced comparable refractive and visual outcomes. The marginal benefit of microincision surgery should be balanced against surgical complexity and intraocular lens injector compatibility when planning cataract procedures.