Fig. 1

Representative images for the measurement of vessel diameter using ImageJ. A Representative image showing the utilization of 78D lens in capturing the fundus image; B Image calibration by setting a scale bar with 300× magnifications; C The diameter of retinal vessel that crossed through the circumferential zone of 0.5-to-1-disc diameter from the optic disc margin . Blue arrow: light rays forming real inverted fundus image, yellow arrow: illuminating light rays from light source, green line: venous diameter, V: venous, A: arterial