“…1 Some diseases, such as hypertension, diabetes, and atherosclerosis, can generate abnormal changes in the width of retinal blood vessels, 2,3 leading vessels to thicken or narrow in some way or to undergo other morphological changes. [4][5][6] Accurate measurement of vessel width can help doctors make precise judgments about the disease. However, because fundus images are sometimes uneven in luminance and retinal vessels are so tiny and complex in structure that it is difficult to be distinguished with naked eyes, manual measurement of the vessel width requires heavy workload and is time-consuming and inefficient.…”