A comparison study of corneal topographic changes following 20-, 23-, and 25-G pars plana vitrectomy.

PURPOSE To evaluate and compare corneal topographic changes following pars plana vitrectomy with the 23-gauge (G) and 25-G transconjuntival sutureless vitrectomy system as well as the standard 20-G vitrectomy system. METHODS We prospectively evaluated corneal topographic changes in 45 eyes of 45 patients divided into three groups according to vitrectomy system used (20-, 23-, and 25-G). All patients underwent computer-assisted videokeratography using an EyeSys System 3000 topographer preoperatively and at one week, one month, and three months postoperatively. RESULTS In the 20-G vitrectomy group, we found statistically significant postoperative changes in corneal curvature parameters with an average steepening of 0.98 ± 0.18 D (P<0.001) and 0.93 ± 0.21 D (P<0.001) at one week and one month, respectively. No statistically significant difference was observed at the three-month follow-up visit. In the 23- and 25-G groups, no statistically significant changes in corneal curvature parameters were observed at any postoperative follow-up visit. CONCLUSION Twenty-three-gauge and 25-gauge transconjunctival sutureless vitrectomy did not induce topographic corneal changes following surgery, whereas 20-G vitrectomy was found to induce transient topographic corneal changes that had returned to preoperative levels at three months postoperatively.