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. Author manuscript; available in PMC: 2019 Nov 1.
Published in final edited form as: Ophthalmol Retina. 2018 Jun 8;2(11):1125–1132. doi: 10.1016/j.oret.2018.04.019

Figure 2. Calculation of the ischemic index on ultra-widefield fluorescein angiography images.

Figure 2

(A) Representative ultra-widefield fluorescein angiogram (UWFFA) of an eye with a CRVO included in this study. (B) The ultra-widefield pseudocolor photograph was overlaid and areas of intraretinal hemorrhage were marked (orange). (C) Next, areas of hypofluorescence not corresponding to a hemorrhage (blue) were marked. The non-perfused pixels (blue) were measured and divided by the total number of imaged pixels representing the fundus and multiplied by 100 to calculate the ischemic index (%). Any pixels corresponding to areas of intraretinal hemorrhage (orange) were excluded from this calculation.