Material and Methods: Thirty eyes of thirty patients who had 23 g TSV surgery were included the study. All patients were examined at pre-operative, first week, first month and third month after operation. Corneal topographies were obtained and pre- and post-operative corneal astigmatism values were also measured. SIA was calculated by using pre- and postoperative corneal astigmatism values and axises with the method which developed by Jaffe and Clayman.

Results: Post-operative mean SIA values were 0.67±0.34 (0.10-1.75) D, 0.4±0.23 (0.07-1.20) D and 0.22±0.16 (0.01-0.91) D at time points of first week, first month and third month, respectively. The decrease in SIA values through follow-up period was statistically significant (p<0.05) In the post-operative period, oblique astigmatism increased and irregular astigmatism decreased, but these changes were not statistically significant (p>0.05). Seventeen (81%) of 21 eyes with a shift to another meridian at post-operative first week returned normal values in time.

Conclusion: SIA is a side-effect that overshadow the surgical success on visual acuity and quality. In our study it was found to be statistically significant decrease in the values of SIA after the post-operative first week. As a result, we consider that 23 g TSV provides better final refraction and visual acuity values for the patients. Keywords : Corneal topography, surgically-induced astigmatism, 23 gauge transconjunctival sutureless vitrectomy