A Novel Approach to Quantitative Evaluation of Outer Retinal Lesions Via a New Parameter “Integral” in Spectral Domain Optical Coherence Tomography

PURPOSE: The purpose of this study was to design a new parameter “integral” to quantitatively evaluate the spatial cumulative reflectivity of the outer retinal layers in optical coherence tomography (OCT), and to investigate its role in the detection of outer retinal diseases. METHODS: This was a cross-sectional study. Fovea-centered line OCT scans were performed on 60 eyes of 60 healthy volunteers and 44 eyes of 44 patients diagnosed with outer retinal diseases. The integrals of the ellipsoid zone (EZ) and interdigitation zone (IZ) were measured by respectively accumulating the grayscale values of all the pixels within the EZ and IZ at specified locations on the scanning lines, and were then adjusted by calculating their percentages on the outer retina. The integrals of the EZ and IZ were compared between the two groups. RESULTS: The integrals of the EZ and IZ were stably and normally distributed in the healthy eyes, and were significantly lower in eyes with outer retinal lesions than in healthy ones (P < 0.05). Moreover, the integrals of the EZ and IZ were correlated with best corrected visual acuity (BCVA; adjusted R(2) = 0.620) and the presence of outer retinal lesions (Nagelkerke R(2) = 0.767). The area under the receiver operating characteristic (ROC) curve was 0.954 (95% confidence interval [CI] = 0.918–0.990) when the integral was selected as a diagnostic variable. CONCLUSIONS: Obtained from this novel quantification method, the new parameter integral was comparable between different individuals and had the potential to detect outer retinal abnormalities in reflectivity through OCT. TRANSLATIONAL RELEVANCE: Our work verified the feasibility of the new image analysis technique in the detection of the diseases affecting the outer retina.