title: The effect of pterygium surgery on contrast sensitivity and corneal topographic changes.
abstract: OBJECTIVE
  To investigate the effect of pterygium surgery on corneal topography and contrast sensitivity.
  
  
  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.
authors.affiliation: Department of Ophthalmology, Seoul National University Hospital, Seoul, Korea.
authors.forename: Joo Youn
authors.initials: JY
authors.lastname: Oh
authors.forename: Won Ryang
authors.initials: WR
authors.lastname: Wee
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