A disease mainly known as diabetes is causing several side effects on the human body. The most affected part of the human body is the human eye retina. This disease of the retina that can result in loss of vision. This phenomenon is known as Diabetic Retinopathy (DR.)Basically Daibetis reduces the capability of the human body to store and regulate the blood sugar , as a result of this, the retina of human eye gets effected. In the early stages DR is showing the typical result of damaging the human eye retina and further it leads to the Sight-threatening diabetic retinopathy (SDTR) i.e. complete loss of vision.Computer assisted diagnosis is one of the tool which helps to diagnose the diabetic patient by using the results of medical investigations. i.e assisting images, reports, etc. for initializing the treatment. In the screening of diabetes sight-threatening DR plays a vital role. These are some major techniques available till date for machine-driven analysis of STDR, to detect hemorrhages and microaneurysms. With limitations for analysis of STDR, the survey mainly focuses on both the qualitative as well as a quantitative comparison of the existing study.While considering the future work , it is a try to encapsulate the convenient algorithms for easy understanding and informative to the experimenters working in this field so that to understand the previous algorithms in a better way and try to develop the most effective one .