Comparison of Manual versus Automated Choroidal Thickness Measurements Using Swept-Source Optical Coherence Tomography

Purpose: The purpose of this study was to compare the automated and manual choroidal thickness (CT) measures in normal eyes using swept-source optical coherence tomography (SS-OCT). Patients and Methods: This prospective study included 80 eyes from 40 normal volunteers. CT was measured manually and automatically in all eyes using Topcon deep-range imaging-1 SS-OCT. Automatically calculated measures, which are shown as a colored topographic map with nine subfields, defined by the Early Treatment Diabetic Retinopathy Study (ETDRS) style grid, compared to manual measures at the subfoveal area, at four points 1 mm around the fovea as well as at four points 3 mm around the fovea. Results: The mean subfoveal CT (SFCT) was 271.77 ± 78.78 μm for the automatically measured ETDRS map and 282.81 ± 83.74 μm for the manual SFCT measurements. The difference between manual and automated measurement was the smallest in SFCT at 11.03 ± 35 μm and the greatest in the outer temporal area at 48.36 ± 49.83 μm. Manually measured CT was significantly higher ( P < 0.001) in all nine areas compared to automated ETDRS map measurements. Conclusions: Manual measurement of CT is significantly higher than automated measurements. In addition, they cannot replace automated methods.