Skip Navigation LinksHome > February 2014 - Volume 33 - Issue 2 > Prediction of Mean Corneal Power Change After Pterygium Exci...
doi: 10.1097/ICO.0000000000000036
Clinical Science

Prediction of Mean Corneal Power Change After Pterygium Excision

Kim, Sun Woong MD, PhD*,†; Park, Saemi MD; Im, Chan Young MD; Seo, Kyoung Yul MD, PhD§; Kim, Eung Kweon MD, PhD§,¶

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Purpose: The aim of this study was to predict the mean corneal power change preoperatively for simultaneous pterygium excision and cataract extraction.

Methods: This study was performed in 2 stages. First, 66 eyes undergoing pterygium excision were recruited, and the subjects were divided into 2 groups based on a pterygium length of 2.0 mm (group 1: <2.0 mm, group 2: ≥2.0 mm). Keratometric values (K) were measured before, 1 month after, and 3 months after surgery. Multiple regression analyses were used to predict the postoperative mean K using preoperative K and morphological factors that significantly affect corneal power change. In the second stage, the regression equation was applied to 50 eyes (23 with pterygium <2.0 mm and 27 with pterygium ≥2.0 mm) in several clinics. Prediction accuracy was graded based on the difference between the calculated mean K and the postoperative mean K.

Results: In group 1, the mean Ks did not change significantly after the surgery, and therefore, the predicted mean K was not statistically different from the preoperative mean K. In group 2, the horizontal and mean Ks steepened significantly, and the regression analysis predicted the mean K within the range of 0.5 diopter difference in 22 of 31 eyes, showing a better approximation compared with the preoperative mean K (P < 0.001). The prediction accuracy was verified similarly in other clinics, and the regression analysis was useful for pterygium exceeding a length of 2.0 mm.

Conclusions: Pterygium exceeding a length of 2.0 mm induced a significant corneal power change after surgery. The mean K predicted from the regression analysis could be used as an approximation for a simultaneous pterygium and cataract surgery.

© 2014 by Lippincott Williams & Wilkins.


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