Changes in corneal topography after 25-gauge transconjunctival sutureless vitrectomy versus after 20-gauge standard vitrectomy

Purpose: To evaluate the changes in regular and irregular corneal astigmatism after 25-gauge transconjunctival sutureless vitrectomy and 20-gauge standard vitrectomy. Design: Prospective observational comparative case series. Participants: Thirty-two eyes of 32 patients undergoing 25-gauge transconjunctival sutureless vitrectomy and 25 eyes of 24 patients undergoing 20-gauge standard vitrectomy. Methods: Corneal topography was obtained preoperatively and at 2 weeks and 1 month postoperatively. Main Outcome Measures: The dioptric data of the central 3-mm zone of the cornea were decomposed using Fourier harmonic analysis into spherical power, regular astigmatism, asymmetry, and higher-order irregularity. Results: None of the 4 Fourier indices changed throughout the observation period in the 25-gauge group. In the 20-gauge group, regular astigmatism, asymmetry, and higher-order irregularity were increased significantly at 2 weeks after vitrectomy (P<0.05, Wilcoxon signed-ranks test) and returned to preoperative levels by 1 month. The spherical power in the 20-gauge group did not change after surgery. For regular astigmatism, asymmetry, and higher-order irregularity, the 20-gauge group showed significantly greater surgically induced changes than the 25-gauge group (P<0.05, Mann-Whitney U test). Conclusions: Twenty-five-gauge transconjunctival sutureless vitrectomy does not induce significant changes in corneal topography and exerts little influence on the optical quality of the cornea.