DETERMINATION OF VALIDITY OF CORNEAL THICKNESS MEASUREMENT BETWEEN ULTRASOUND PACHYMETRY (US), SCHEIMPFLUG IMAGING (PENTACAM, OCULUS) AND SCANNING-SLIT TOPOGRAPHY (ORBSCAN II, BAUSCH & LOMB) IN HYPEROPIC EYES AFTER LASEK SURGERY

Abstract

Background and Aim: To determine the validity in central corneal thickness (CCT) peripheral corneal thickness (PCT) measured by Scheimpflug imaging (Pentacam, Oculus) and scanning-slit topography (ORBSCAN II, Bausch & Lomb) with that by gold standard method of ultrasound (US) in Hyperopic eyes after LASEK surgery . Materials and Methods: the present study which was based on descriptive and analytic census that carried out in hyperopic patients who undergone LASEK eye surgery in Farabi eye hospital in 2012 and collection of samples lasted for 9 months. The subjects were inspect by ultrasound (US), Scheimpflug imaging ( Pentacam ,Oculus) and scanning-slit topography (ORBSCAN II, Bausch & Lomb) .statistical analysis of collected data was performed using SPSS software version 18 and T-2test method. Results: CT and PCT were evaluated in 28 eyes. CCT measured by Orbscan II had good correlation with those measured by ultrasound pachymetry(r=0.083 and p<0.05) also Orbscan II had good correlation in CCT measurement with Pentacam HR (p<0.05 and r=0.072).PCT measured by Pentacam HR had good correlation with those ultrasound pachymetry readings and there is no considerable discrepancy between two method. 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 pachymetry (sig=0.01, t=-2.74, p<0.05). Conclusion: Pentacam HR and ORBSCAN II showed good correlation with US in CCT measurement but in PCT measurement Pentacam HR had better correlation comparing with ORBSCAN II for hyperopic patient after LASEK refractive surgery Key Words: hyperopia, Pentacam HR, ORBSCAN, LASEK, Ultrasound