Abstract
Abstract: :
Purpose: The 25–gauge transconjunctival sutureless vitrectomy allows for self–sealing transconjunctival sclerotomies and has the potential to increase efficiency of a variety of vitreoretinal surgeries. The purpose of this study was to quantitatively evaluate changes in corneal regular and irregular astigmatism after 25–gauge transconjunctival sutureless vitrectomy and 20–gauge standard vitrectomy. Methods: Subjects were 27 eyes of 27 patients undergoing 25–gauge transconjunctival sutureless vitrectomy (25G group) and 25 eyes of 24 patients undergoing 20–gauge standard vitrectomy (20G group). Corneal topography was taken preoperatively and at 2 weeks, 1 month postoperatively. The dioptric data of central 3– and 6–mm zone of the cornea were decomposed using Fourier harmonic analysis into spherical component, regular astigmatism, decentration component, and higher order irregularity. Results: In the 25G group, all four refractive parameters did not change significantly throughout the observation period. In the 20G group, regular astigmatism, decentration component, and higher order irregularity significantly increased 2 weeks after vitrectomy (p<0.05, Dunnett), which returned to the preoperative level by 1 month. The spherical component in the 20G group did not fluctuate by surgery. For all Fourier indices except for decentration, the 20G group showed significantly greater amount of changes than did the 25G group (p<0.05, unpaired t–test). Similar results were obtained for both 3– and 6–mm zone. Conclusions: The 25–gauge transconjunctival sutureless vitrectomy did not induce significant changes in corneal topography, and thus exerts little influence on the optical quality of the cornea.
Keywords: cornea: clinical science • topography • vitreoretinal surgery