Figure 1.

Methods used for analysis of scans

Figure 1A illustrates the location of the scans used. Macular scans (solid line marked i) were 30 degrees long and centered on the fovea. Peripapillary scans (dotted circle marked ii) were taken along a circle 12 degrees in diameter, centered on the optic disc.

In Figure 1B shows a Spectral domain optical coherence tomography scan of the macula with the choroid delineated over 6 mm (from one set of dotted lines/arrows to the other) by 8 marked locations, centered on the fovea. The outer margin of the retinal pigment epithelium (RPE) was considered the anterior margin of the choroid (up-pointing arrows) and the choroidal-scleral interface (CSI) was the posterior margin of the choroid (down pointing arrows). The image was exported to ImageJ and the borders of the choroid were drawn by connecting the marked locations, leading to calculation of measured choroidal area. This area was divided by 6000 µm to estimate average macular choroidal thickness (in µm).

In Figure 1C is a scan of the peripapillary region scan in which the circular area is arrayed linearly, with the horizontal meridian at the dotted line/arrows and superior to the left and inferior to the right. As in macular scans, the RPE (up-pointing arrows) and the CSI (down-pointing arrows) delimited the choroid. After export to ImageJ for estimation of total area, this value was divided by a scan length determined for each eye by an individualized scaling factor to derive average peripapillary choroidal thickness.