Quantification of Retinal Capillary Abnormalities

Micrographs for quantification were taken with a Canon Rebel XSi digital camera (Canon, Tokyo, Japan) attached to an Olympus CKX41 microscope via an LM scope C-mount. For acellular capillary counts, 12 micrographs were taken from 3 randomly selected areas in each of the 4 retinal quadrants and analyzed at a final magnification of ×200. We categorized abnormal capillary features into three groups: the first group is definitive acellular capillaries; the second group is pericyte processes (described in our paper^{9 (link)}) and the third group is ambiguous abnormal features that were very short or sometimes partially obscured by other vessels. The total area used for quantification corresponded to approximately 8.5% of the whole retinal area. The counts were quantified using FIJI computer software without any additional plugins by two masked graders.