Abstract
Purpose: :
To compare central and peripheral corneal thickness (CCT, PCT) using scheimpflug system (Pentacam), high-speed optical coherence tomography (Visante OCT) and ultrasound pachymetry (UP), in normal, keratoconus suspect and post LASIK eyes.
Methods: :
We retrospectively analyzed CCT and PCT from 163 eyes (83 patients) using UP, Pentacam and Visante OCT in keratoconus suspect, normal and post LASIK eyes from January 2006 to March 2008. Influence of age and absolute magnitude of corneal thickness were also analyzed. Analysis was performed with multivariate generalized estimating equations, multivariate linear regression and linear regression plots.
Results: :
UP CCT measurements were consistently higher than Pentacam (6.5µm±1.8; p<0.0005) and Visante OCT (7.5µm±1.4; p<0.0005) for normal eyes, and this difference was not significantly increased with keratoconus suspicion, age or different absolute magnitude of corneal thickness (p>0.05). Pentacam measurements were significantly even lower than UP in post LASIK eyes (p<0.0005). Pentacam and OCT showed non significant mean difference in CCT measurements (0.9±1.4µm; p>0.5). However, in post LASIK eyes Pentacam measurements were lower than OCT CCT (p<0.0005). PCT was higher in Pentacam than in Visante OCT, showing more agreement with increasing age (p=0.017).
Keywords: cornea: clinical science • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • refractive surgery