Comparison of corneal pachymetry using ultrasound and Orbscan II

Purpose: To compare Orbscan II pachymetry with ultrasonic pachymetry in eyes having corneal refractive surgery. Settings: Instituto Oftalmologico de Alicante, Alicante, Spain. Methods: In this comparative prospective study, 72 eyes (36 patients) were divided into 4 groups: Group 1, 16 eyes with haze after photorefractive keratectomy (PRK) Group 2, 12 eyes with no haze after PRK; Group 3, 24 eyes that had uneventful laser in situ keratomileusis; Group 4, 20 normal eyes. The corneal thickness was measured in all eyes by the Orbscan 11 (version 3.27.10, Orbtek Inc.) and then by ultrasonic pachymetry (DHC 500, Technology Inc.). Results: The results between the 2 systems of pachymetry were significant in Group I (P <.0001) and not significant in Groups 2, 3, and 4 (P=.056, P=.051, and P=.68, respectively). A statistically significant correlation existed between the grade of haze and the decrease in Orbscan readings (C = -0.821, P <.0001). Conclusion. The Orbscan 11 pachymetry measurements correlated with the ultrasound measurements in eyes with clear corneas. Haze after PRK decreased the Orbscan pachymetry. J Cataract Refract Surg 2002; 28:248-252 (C) 2002 ASCRS and ESCRS.