Introduction: The segmentation of retinal blood vessel now a day is one of the most important factors which decides the performance of a Computer-aided design (CAD) based system. Segmentation is the process of extracting the region of interest i.e. the disease in the image. The boundaries of retinal blood vessels need to be segmented accurately as an eye surgeon cannot be able to predict the area of disease in case segmentation not done accurately. Objective: This proposed method aims to segment retinal blood vessels using morphological operation which robustly extract the feature. The final image is obtained by using distance-based clustering. Results: The proposed method had shown an accuracy of more than 98.15% and the images are enhanced as the peak signal to noise ratio (PSNR) value is more than 50. Conclusion: The proposed method is efficient in contrast with various existing techniques.