The aim of this survey is to list the various disease predictions from retinal fundus images and various methods used to detect the disease. This paper gives a detailed description about the various diseases predicted in retina by comparing retinal fundus image structure. Till now, the prediction of various diseases such as diabetic retinopathy, cardiovascular disease and other eye problems had been predicted by using retinal fundus images. Next, a comparitive study of the various methods followed using image processing to find out the diseases from retinal fundus images, is provided. The basic matrices observed to predict the diseases are optic disc,nerve cup and rim. To find the differences in the basic matrices, image processing techniques such as mask generation, colour normalization, edge detection, contrast enhancement are used. The datasets that are used for retinal image inputs are STARE, DRIVE, ONHSD, ARIA, IMAGERET. The survey at the end, discusses the future work for the possibilities of predicting gastreointestinal problems via retinal fundus images.