Fig. 1

Measurement of subfoveal and peripapillary choroidal thickness (CT). Subfoveal CT (white arrow) was measured perpendicularly from the outer surface of the line corresponding to the retinal pigment epithelium (RPE) to the inner chorioscleral junction (a). A 360°, 3.4-mm-diameter circle scan provided retinal thickness (RT) and retinal nerve fiber layer (RNFL) thickness from four sectors around the optic disc. The thickness value of each sector represents the mean thickness of the layers within each sector (b). The RT of each sector was determined between two segmentation lines of the internal limiting membrane (ILM) and RPE. The segmentation line of the RPE was then modified to the chorioscleral junction by the examiner using the modification tool in the optical coherence tomography image viewer program (c). Chorioretinal thickness between the ILM and chorioscleral junction was obtained, and CT was calculated by subtracting the RT from the chorioretinal thickness of each sector. T, temporal; S, superior; I, inferior; N, nasal