Retinal thickness measurements with optical coherence tomography and the scanning retinal thickness analyzer

Purpose: To assess the reproducibility of retinal thickness measurements in normal subjects and to compare foveal thickness using optical coherence tomography (OCT) and the scanning retinal thickness analyzer (RTA). Methods: Two examiners performed foveal thickness measurements in 24 eyes of 12 healthy subjects using both OCT and the scanning RTA. Intraclass correlation coefficients (ICC) (intra-examiner and inter-examiner) were calculated for the paired foveal thickness measurements obtained with each instrument. Results: The average foveal thicknesses measured with OCT and the scanning RTA were 155.1 +/- 14.9 mum and 107.8 +/- 18.6 mum, respectively. The intra-examiner ICCs from the two sessions using the OCT and the scanning RTA were 0.99 and 0.78 and 0.89 and 0.99, respectively. The inter-examiner ICCs of the OCT and the scanning RTA were 0.99 and 0.99, respectively. There was a significant correlation between the foveal thickness measurements with these two instruments (R-2 = 0.629, P < 0.0001). Conclusion: The foveal thicknesses measured using OCT and the scanning RTA in healthy subjects agreed with the previously reported data on foveal thickness. Both instruments can reproducibly quantitate foveal thickness.