Spectral domain-optical coherence tomography image contrast and background color settings influence identification of retinal structures

Purpose: To evaluate image contrast and color setting on assessment of retinal structures and morphology in spectral-domain optical coherence tomography. Methods: Two hundred and forty-eight Spectralis spectral-domain optical coherence tomography B-scans of 62 patients were analyzed by 4 readers. B-scans were extracted in 4 settings: W + N white background with black image at normal contrast 9; W + H white background with black image at maximum contrast 16; B + N black background with white image at normal contrast 12; B + H black background with white image at maximum contrast 16. Readers analyzed the images to identify morphologic features. Interreader correlation was calculated. Differences between Fleiss-kappa correlation coefficients were examined using bootstrap method. Any setting with significantly higher correlation coefficient was deemed superior for evaluating specific features. Results: Correlation coefficients differed among settings. No single setting was superior for all respective spectral-domain optical coherence tomography parameters (P 0.3773). Some variables showed no differences among settings. Hard exudates and subretinal fluid were best seen with B + H (0.46, P 0.0237 and 0.78, P 0.002). Microaneurysms were best seen with W + N (0.56, P 0.025). Vitreomacular interface, enhanced transmission signal, and epiretinal membrane were best identified using all color/contrast settings together (0.44, P 0.042, 0.57, P 0.01, and 0.62, P ≤ 0.0001). Conclusion: Contrast and background affect the evaluation of retinal structures on spectral-domain optical coherence tomography images. No single setting was superior for all features, though certain changes were best seen with specific settings.