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Changes in corneal topography following 25–gauge transconjunctival sutureless vitrectomy and 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: Subjects were 32 eyes of 32 patients undergoing 25-gauge transconjunctival sutureless vitrectomy (25G group) and 25 eyes of 24 patients undergoing 20-gauge standard vitrectomy (20G group). Methods: Corneal topography was obtained preoperatively and at 2 weeks and 1 month postoperatively. Main Outcome Measures: The dioptric data of the central 3mm zone of the cornea were decomposed using Fourier harmonic analysis into spherical power, regular astigmatism, asymmetry, and higher-order irregularity. Results: None of the four Fourier indices changed throughout the observation period in the 25G group. In the 20G 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 the preoperative levels by 1 month. The spherical power in the 20G group did not change after surgery. For regular astigmatism, asymmetry and higher-order irregularity, the 20G group showed significantly greater surgically induced changes than the 25G group (p<0.05, Mann-Whitney’s U test). Conclusions: The 25G transconjunctival sutureless vitrectomy does not induce significant changes in corneal topography, and exerts little influence on the optical quality of the cornea.