Effect of pterygium surgery on corneal topography: a prospective study.

Abstract

To evaluate the effect of pterygium surgery on the corneal topography and visual acuity and to correlate the results with patients' features. A prospective, nonrandomized, self-controlled trial. Computerized videokeratography was performed in 54 patients (55 eyes) with primary pterygium before and after pterygium excision using bare sclera technique combined with intraoperative mitomycin C. The following topographic parameters were noted: corneal astigmatism at the central 3 mm; total mean refractive power of the whole cornea; surface regularity index (SRI); and surface asymmetry index (SAI). Best corrected visual acuity of the operated eyes was also examined. Differences between pre- and postoperative values were evaluated statistically with paired two-tailed t test and two-tailed Pearson correlation. The respective values (mean +/- SD) before and after treatment of the study parameters were as follows: simulated keratometric astigmatism at 3 mm, 3.12 +/- 2.43 and 2.51 +/- 2.50 (P = 0.05); mean SRI, 0.99 +/- 0.65 and 0.90 +/- 0.65 (NS); mean SAI, 1.37 +/- 1.69 and 1.23 +/- 1.49 (NS). Best corrected visual acuity was 20/40 preoperatively and 20/25 postoperatively (P < 0.01). Both pre- and postoperative astigmatism correlated with pterygium size. Pterygium surgery significantly reduces refractive astigmatism and improves SRI, SAI, and best corrected visual acuity.