Topographic changes after excision surgery of primary pterygia and the effect of pterygium size on topograpic restoration.

Abstract

To assess the effect of pterygium size on time-course change of corneal topography after excision surgery of primary pterygium. Retrospective case series included eyes that underwent excisions of primary pterygium. Pterygium size was graded according to the advancing edge position: less than one third of corneal diameter (grade 1), outside the pupil (grade 2), and within the pupillary area (grade 3). Time-course changes in corneal refractive power, astigmatism, and irregularity (surface regularity and asymmetry indices) in corneal topographies over 12 months postoperatively were compared between the pterygium size grades. Pterygium excision was performed on 562 eyes, consisting of 119, 338, and 105 eyes with grades 1 to 3, respectively. Grade 1 did not change in corneal irregularity, and there was no difference between grades 1 and 2, except for corneal astigmatism at 6 months. Grade 3 showed significantly higher corneal refractive power and irregularity than grade 1 until 3 and 6 months, respectively, whereas corneal astigmatism was higher over 12 months. Topographic changes after primary pterygium excision were associated with pterygium size. Pterygium advancing over the pupillary area required 6 to 12 months for corneal topography restoration, resulting in slow recovery of visual acuity.