Glaucoma is an eye disease that usually occurs with the increased Intra-Ocular Pressure (IOP), which damages the vision of eyes. So, detecting and classifying Glaucoma is an important and demanding task in recent days. For this purpose, some of the clustering and segmentation techniques are proposed in the existing works. But, it has some drawbacks include inefficient, not accurate and estimates only the affected area. In order to solve these issues, a Neighboring. Differential Clustering (NDC) – Intensity Variation Masking (IVM) are proposed in this paper. The main intention of this work is to extract and diagnose the abnormal retinal image by identifying the optical disc. This work includes three stages such as, preprocessing, clustering and segmentation.