Manual Versus Automated Choroidal Thickness Measurements Using Swept-source Anterior Segment OCT

A single expert retinal specialists used a Topcon DRI-1 SS-OCT to do the Choroidal Thickness measurements. A 12, 9-mm radial line scan procedure was performed. Each radial line was automatically scanned 32 times in the same spot, followed by the creation of 12 high-resolution average B-scan images. Each scan was double-checked to confirm that it was centred on the fovea. Only scans of good quality were included. The perpendicular distance between the outer border of the RPE and the junction of the choroid and sclera was used to calculate CT. It was calculated automatically using the mapping software incorporated into the device and displayed as a colourful topographic map with nine subfields defined by the Early Treatment Diabetic Retinopathy Study (ETDRS) style grid.