Both tetracaine and proparacaine had toxic effects on stromal keratocytes related not only to drug concentrations but also to time exposure. These findings underscore the widespread concern that anesthetic drugs may affect corneal stromal wound healing after PRK.

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.

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