Materials and Methods: 26 eyes of 24 patients who underwent trabeculectomy surgery included into this prospective study. Refractive parameters measurements performed with autorefractoceratometry (horizontal and vertical power and axis), corneal topography (anterior chamber depth- ACD and corneal thickness-CT) and biometry (axial length- AL) along with complete opthalmic examination performed in preoperative and postoperative 3rd month. Surgically induced astigmatism was calculated with vector analysis. Paired t test, correlation analysis, logistic regression analysis and χ2 test were used in the statistical analysis.

Results: The mean preoperative intraocular pressure (IOP) was 24.13±8.80 mmHg while the mean ACD was 2.39±0.44 mm and mean AL was 22.93±1.20 mm; these values have been determined as 12.66±4.75 mmHg, 2.28±0.43 mm and 22.70±1.12 mm, respectively in postoperative period, and it has been seen that the difference between the averages are statistically significant (p=0.000, p=0.040, p=0.034). As a result of the vector analysis, 14 of eyes (53.8%) had with the rule astigmatism and 12 of eyes (46.2%) had against the rule astigmatism. Evaluation of the scleral flap area, number of sutures and internal ostium area, which are parameters that can affect these results, with the logistic regression analysis revealed that “scleral flap area” may have a statistically significant effect (p=0.026).

Conclusion: In early postoperative period the ACD and AL were decreased and astigmatism was also changed. While the ACD and AL reduction were related to the amount of IOP reduction, the determinant parameter for the surgically induced astigmatism type was the “scleral flap area”. Keywords : Trabeculectomy, keratometry, corneal topography, biometry