Glaucoma is a diseases that damage the optic nerve and can result in visual loss. Glaucoma pathophysiology is still not fully understood. Vasculopathy may be one of the possible causes of nerve damage. One of techniques for retinal arteriolar abnormalities grading is quantifying retinal arteriolar central light reflex. This thesis presents technique for measuring central light reflex width-to-retinal vessel diameter ratio (CRR) from fundus photographs. Using Canny edge detection technique and Vessel enhancement filtering for retinal vessel segmentation, CRRs from glaucoma and normal eyes were compared to examine differences and associations. CRRs were evaluated on fundus photographs from 92 normal eyes and 68 glaucoma eyes. In each photograph, CRRs from four retinal vessels, including arteries and veins in the inferotemporal and superotemporal regions were quantified. From Z-test, mean CRRs of all four retinal arteries and veins were significantly higher in persons with glaucoma than in those without glaucoma (0.30 vs. 0.28, p = 0.033 for inferotemporal artery, 0.29 vs. 0.27, p = 0.005 for inferotemporal vein, 0.31 vs. 0.28, p < 0.001 for superotemporal artery, and 0.30 vs. 0.27, p = 0.002 for superotemporal vein). From these results, CRRs can help in glaucoma diagnosis but overall patient data still necessary because difference between mean CRRs of persons with glaucoma and without those were low so using only CRRs would not accurate.