advertisement
Abstract #22520 Published in IGR 11-1
Central corneal thickness measurements with optical coherence tomography and ultrasound pachymetry in healthy subjects and in patients after photorefractive keratectomy
Schneider M; Borgulya G; Seres A; Nagy Z; Nemeth JEuropean Journal of Ophthalmology 2009; 19: 180-187
PURPOSE: To compare central corneal thickness measurements made using two different methods, optical coherence tomography (OCT) and ultrasound pachymetry, applied both in normal eyes and in eyes on which photorefractive keratectomy (PRK) had been performed. A second objective was to assess the intrasession variability of OCT measurements. METHODS: In this prospective study, central corneal thickness was measured in 20 normal subjects (normal group) and in 20 PRK patients using the StratusOCT instrument model 3000 (Carl Zeiss Meditec), and also with an ultrasound pachymeter. Five OCT measurements were performed using the Fast Macular Thickness protocol. Corneal thickness data were obtained with the Scan Profile analysis protocol. The OCT measurement results were compared with the mean value of three ultrasound pachymetry measurements for the same eye. RESULTS: The pachymetry-OCT correlation coefficients were 0.96 and 0.97 in the normal and PRK groups, respectively (p=0.14). Neither linear regression nor Bland-Altmann analysis revealed any significant systematic measurement error. Intrasession standard deviations in the normal and PRK groups were 4.9 μm and 3.8 μm, respectively. CONCLUSIONS: Noncontact central corneal thickness measurements made using the StratusOCT instrument are accurate and reproducible, both in normal subjects and in post-PRK patients. The instrument system does not need any modifications to correctly detect and measure the center of the cornea.
Dr. M. Schneider, Department of Ophthalmology, Semmelweis University, Faculty of Medicine, Budapest, Hungary
Classification:
6.9.2.1 Anterior (Part of: 6 Clinical examination methods > 6.9 Computerized image analysis > 6.9.2 Optical coherence tomography)
6.12 Ultrasonography and ultrasound biomicroscopy (Part of: 6 Clinical examination methods)
2.2 Cornea (Part of: 2 Anatomical structures in glaucoma)