Comparison of corneal thickness in candidates for photorefractive keratectomy (PRK) using three methods, Orbscan II, Pentacam, and ultrasound

Abstract

Background: The aim of this study was to compare the central corneal thickness measured by Orbscan II, ultrasound and Pentacam in patients undergoing photorefractive keratectomy (PRK). Methods: This descriptive-analytic study was carried out during one year in Feyz hospital, Isfahan city, Iran in 2013. The sample included 84 eyes of 84 patients undergoing photorefractive keratectomy with no history of corneal or intra-ocular surgery. Each patient's corneal thickness was measured and recorded using 3 devices of Orbscan, ultrasound and Pentacam. The obtained data were analyzed using SPSS software. Findings: Central corneal thickness (CCT) measured by Orbscan II had good correlation with those measured by ultrasound (r = 0.077, P < 0.050). Orbscan II had good correlation in central corneal thickness measurement with Pentacam (r = 0.072, P < 0.050). Peripheral corneal thickness (PCT) measured by Pentacam had good correlation with those measured by ultrasound and there was no considerable discrepancy between the two methods. Orbscan II had good correlation in superior, inferior and temporal corneal thickness but there was considerable discrepancy in nasal corneal thickness measured by Orbscan II with those of ultrasound (r = 0.420, P < 0.050, t = -2.74, P = 0.010). Conclusion: Pentacam and Orbscan II showed good correlation with ultrasound in central corneal thickness measurement; however, in peripheral corneal thickness measurement, Pentacam had better correlation compared to Orbscan II in patients undergoing photorefractive keratectomy. © 2017, Isfahan University of Medical Sciences(IUMS). All Rights Reserved.