The effect of pterygium surgery on contrast sensitivity and corneal topographic changes

PURPOSE To investigate the effect of pterygium surgery on corneal topography and contrast sensitivity. PATIENT AND METHODS The IRB approved this prospective, nonrandomized, self-controlled study. Computerized videokeratography (Orbscan II) was performed in 36 patients with primary pterygia, both before and 1 month after pterygium excision with limbal-conjunctival autografting. The topographic parameters were compared. Spatial contrast sensitivity testing was performed using VCTS 6500. Differences between preoperative and postoperative values were evaluated statistically. RESULTS The mean Sim K astigmatism and irregularity index, significantly decreased after pterygium surgery. The mean refractive power significantly increased after the operation. The "with-the-rule" astigmatism induced by pterygium became "against-the-rule" astigmatism after pterygium removal (P = 0.041). The contrast sensitivity of 6, 12, and 18 cycles per degree, significantly increased from 1.55 +/- 0.28, 0.97 +/- 0.47, and 0.29 +/- 0.16 to 1.72 +/- 0.18, 1.21 +/- 0.44, and 0.65 +/- 0.48, respectively (P = 0.007, <0.001, <0.001, respectively). CONCLUSIONS Pterygium surgery significantly reduces corneal topographic astigmatism and improves contrast sensitivity.