Abstract: To investigate whether retinal vessel caliber measurements on optical retinal Photography are affected by light and dark exposure prior to photography. Whether the vessel caliber changes during an imaging sequence ,Digital optical retinal photographs which is obtained from 32 healthy Adults in two separate image sequences of six images during 1 min; one sequence with of dark exposure and one with of light exposure for 10 min each of prior to imaging. Retinal arteriolar and venular calibers were measured computer-assisted and summarized as central retinal artery and vein equivalents (CRAE and CRVE).from that Outcome measures were difference in calibers after prior light versus prior dark exposure also difference in calibre during each of the two imaging sequences. We also present a 3D reconstruction of retinal blood vessel trees using two views of fundus images.

Keywords: Vessel segmentation, artery/vein classification, retinal images, graph, vascular caliber, etc.