Fig. 1
From: Effects of refractive power on quantification using ultra‐widefield retinal imaging
Measurement (quantification) of optic disc area. Ultrawide-field (UWF) retinal images were projected onto a flat map to preserve the peripheral aspect ratio to a best-fit 24 mm globe model. With stereographically projected UWF images, the optic disc area was outlined with 15–17 points where the disc margin meets the blood vessel. In each case, the optic disc area was measured in square millimeters (mm2) by summing the anatomically-corrected sizes of all pixels that comprise the disc margin