Early and late effects of pterygium surgery on corneal topography

The aim of this study was to compare the corneal topographic changes at the early and late postoperative period after pterygium surgery.

Sixteen eyes of 15 patients with primary pterygium were included in the study. All of the pterygia were excised primarily. Computerized corneal topography measurements were taken before surgery and at the second week (postoperative early period) and third month (postoperative late period) after the operation. Keratometric astigmatism, total mean corneal refractive power, and flattened or steepened areas of the cornea were detected at each visit. The topographical changes were evaluated using the analysis of variance. Multiple comparison analyses were made with the Tukey HSD test.

Keratometric astigmatism was 2.58 +/- 2.33 diopters (D) at the preoperative period, 1.30 +/- 1.24 D at the postoperative early period, and 0.61 +/- 0.38 D at the postoperative late period (P < .001). The surgically induced corneal astigmatism was 3.23 +/- 2.33 D (range, 0.52 to 8.32 D) at the postoperative early period and 2.70 +/- 2.24 D (range, 0.47 to 7.72 D) at the postoperative late period (P = .287). Astigmatism was 81.25% with-the-rule at the preoperative period, 43.75% oblique and 37.50% against-the-rule at the postoperative early period, and 62.50% with-the-rule at the postoperative late period. Total mean corneal refractive power was 42.51 +/- 1.99 D at the preoperative period, 43.95 +/- 1.58 D at the postoperative early period, and 43.89 +/- 1.80 D at the postoperative late period (P = .014).

Corneal topographic changes induced by pterygium greatly improve at the postoperative early period. However, normal corneal topography patterns are formed at the postoperative late period.