The MAs have diameters between 10 and , are round in shape, and their color is similar to blood vessels (BVs) (red),5,6 as shown in Fig. 1. Detection of MAs is challenging due to the variation in MA size, low and varying contrast, uneven illumination, and variation in fundus image background. MA detection is not a new topic; many researchers have worked on it since the early 1980s.7,8 Though the performance of the automatic system in digitized fluorescein angiograms is somewhat on par with a human grader,9 it is considered to be an invasive method, as fluorescein sodium dye is injected into the eye. The associated risk of complication or adverse reaction can include transient nausea, occasional vomiting, and so on, and in very rare cases can cause death. Thus most of the current research is moving toward color fundus photography, which is a noninvasive imaging method. In the absence of contrast enhancing agent, color fundus images inevitably suffer from low contrast. The performance of the fundus image-based system is, as expected, limited and remains as an open issue in retinal image analysis.