**2.3 Glaucoma detection using vessel segmentation**

According to the literature survey due to progression of Glaucoma, blood vessel diameter decreases [19–22], and smaller diameter vessels around the optic disc start diminishing and disappearing. We have employed these aspects of vessels as features to detect the Glaucoma at an early stage. **Figure 13** clearly shows these aspects. The region where these significant vessels of interest are present in a small area around the optic disc in the image for detection of Glaucoma is considered as region of interest (ROI).
