Reproducibility of Spectral-Domain Optical Coherence Tomography Total Retinal Thickness Measurements in Mice

PURPOSE. To test the reproducibility of spectral-domain optical coherence tomography (SD-OCT) total retinal thickness (TRT) measurements in mice. METHODS. C57Bl/6 mice were anesthetized, and three repeated volumetric images were acquired in both eyes with SD-OCT (250 A-scans x 250 frames x 1024 samplings), centered on the optic nerve head (ONH). The mice were repositioned between scans. TRT was automatically measured within a sampling band of retinal thickness with radii of 55 to 70 pixels, centered on the ONH by using custom segmentation software. The first volumetric image acquired in a given eye was used to register the remaining two SD-OCT images by manually aligning the en face images with respect to rotation and linear translation. Linear mixed-effects models were fitted to global and quadrant thicknesses, taking into account the clustering between eyes, to assess imprecision (measurement reproducibility). RESULTS. Twenty-six eyes of 13 adult mice (age 13 weeks) were imaged. The mean global TRT across all eyes was 298.21 mu m, with a mouse heterogeneity standard deviation (SD) of 4.88 mu m (coefficient of variation [CV] = 0.016), an eye SD of 3.32 mu m (CV = 0.011), and a device-related imprecision SD of 2.33 mu m (CV = 0.008). The superior quadrant had the thickest mean TRT measurement (310.38 mu m) and the highest (worst) imprecision SD (3.13 mu m; CV = 0.010), and the inferior quadrant had the thinnest mean TRT (291.55 mu m). The quadrant with the lowest (best) imprecision SD was in the nasal one (2.06 mu m; CV = 0.007). CONCLUSIONS. Good reproducibility was observed for SD-OCT retinal thickness measurements in mice. SD-OCT may be useful for in vivo longitudinal studies in mice. (Invest Ophthalmol Vis Sci. 2010; 51: 6519-6523) DOI:10.1167/iovs.10-5662