Repeatability and reproducibility of retinal thickness measurements in diabetic patients with spectral domain optical coherence tomography.

ABSTRACT

BACKGROUND: To determine the repeatability and reproducibility of optical coherence tomography (OCT) Spectralis retinal thickness measurements in diabetic patients with clinically significant macular edema (CSME). METHODS: Twelve eyes of 12 volunteers (without macular pathology - control group) and 21 eyes of 21 diabetic patients with CSME were included in the study. Reproducibility, repeatability, intraclass correlation coefficients (ICCs) and intrasession correlation coefficients were tested with 20 × 15 degree raster scans consisting of 19 high-resolution line scans that were repeated three times by two experienced examiners. RESULTS: In the control group, examining all regions, coefficient of repeatability was less than 1.1%, while coefficient of reproducibility was less than 2.2%. In diabetic patients, examining all regions, coefficient of repeatability was less than 2.6%, while coefficient of reproducibility was less than 2.4%. ICCs were, respectively, greater than or equal to 0.98 in the control group and 0.99 in diabetic patients. Intrasession coefficients of variation were less than 0.4% in the control group and less than 0.5% in diabetic patients. CONCLUSION: Retinal thickness measurements are repeatable and reproducible with OCT Spectralis in both the control group and diabetic patients. The results indicate that a change in central subfield thickness exceeding 12 µm and 3% in the diabetic patients is likely to be real.