Purpose: To assess the agreement between Orbscan 3, Pentacam HR and ultrasound pachymetry (Palm Scan AP 2000) in measuring central corneal thickness.
Methods: Prospective observational cross-sectional study of ninety-two eyes of 48 patients with normal corneas was conducted. Central corneal thickness was measured via Pentacam HR, Orbscan 3 and ultrasound pachymetry. Bland-Altman analysis was used to demonstrate agreement between various methods.
Results: Ninety-two eyes of 46 subjects were enrolled. The mean age was 29.67 years (18-59). The average measurements of central corneal thickness were 545.73 ± 29.35 μm, 549.34 ± 29.14 μm and 545.78 ± 31.48 μm for the Pentacam HR, Orbscan and ultrasound pachymetry, respectively. The three devices measurements are closely correlated, with Pearson correlation coefficient ranging from 0.868 to 0.929. The 95 % limits of agreement were 25.2 to - 18 μm between Orbscan and Pentacam central corneal thickness, 25.2 to - 25.7 μm between Pentacam and pachymetry central corneal thickness and 34.4 to - 27.2 μm between Orbscan and pachymetry central corneal thickness.
Conclusion: In spite of advancement of Orbscan 3, still there are wide agreement limits between CCT measurements obtained via Orbscan 3, Pentacam HR and ultrasound pachymetry; thus, interchangeable use in clinical practice is not recommended.
Keywords: CCT; Corneal thickness; Orbscan 3; Pentacam HR; Ultrasound pachymetry.