Eyes are part of an organ in a human which is important for vision especially retinal. Retinal images are used to detect and diagnose many diseases such as diabetes or hypertension. Diabetic retinopathy is the name given to disease of the retina due to diabetes. The eyes have to be examined by an optometrist to detect the lesion. Diabetic retinopathy symptoms may include blurred vision, difficulty reading and also vision loss. Generally, DR patients perceive no symptoms until visual loss develops which happens usually in the later disease stages when the treatment is less effective. DR is not a curable disease, but laser treatment can prevent major vision loss if detected in the early stages. In this paper, a fundamental of DR was studied included stages, causes, symptoms, and risks. This study will give the direction for a researcher in order to propose a new DR detection method.
