1. A computer-implemented method for automatically measuring changes in retinal disease, retinal pigment epithelial disease, or choroidal disease, the method comprising: retrieving, with one or more processors, a set of images of a fundus; selecting, by the one or more processors, a plurality of images from the set of images, wherein the plurality of images includes images of the fundus captured at successive times; co-registering, by the one or more processors, the plurality of images, wherein co-registering the plurality of images includes: detecting a plurality of blood vessel locations within each of the plurality of images by filtering each of the plurality of images to identify blood vessels, correlating the plurality of images by determining matches between the detected plurality of blood vessel locations in one of the plurality of images with the corresponding plurality of blood vessel locations in each remaining image in the plurality of images, and transforming each remaining image in the plurality of images such that blood vessel locations in the remaining image are proximate to the detected plurality of blood vessel locations in the one of the plurality of images based upon alignment of the matched blood vessel locations; pre-processing, by the one or more processors, the plurality of images such that the quality, contrast, and gain of each of the plurality of images is made similar; performing a comparison, by the one or more processors, of the plurality of co-registered and pre-processed images to determine a change in retinal disease, retinal pigment epithelial disease, or choroidal disease, by: identifying a sampled window representing an equivalent area of the fundus within each of the plurality of images, dividing the sampled window into a plurality of grid boxes, wherein each grid box is a predetermined area within the sampled window such that the plurality of grid boxes do not overlap and such that the plurality of grid boxes together cover the entire sampled window, subtracting the mean observed light intensity of image pixels within each of the grid boxes of an older image from the mean observed light intensity of image pixels within each of the corresponding grid boxes of a more recent image to produce a difference matrix indicating differences in mean observed light intensity for each pair of corresponding grid boxes, determining a plurality of changed grid boxes representing regions of the fundus having an increased or decreased value of mean observed light intensity as compared with a threshold value based upon the difference matrix, and calculating disease metrics based on the plurality of changed grid boxes representing the regions of the fundus having an increased or decreased value of mean observed light intensity; and generating, by the one or more processors, an indication of the change in retinal disease, retinal pigment epithelial disease, or choroidal disease to be displayed to a user of a computing device, the indication of the change in retinal disease including a visual display of the plurality of changed grid boxes representing the regions of the fundus having an increased or decreased value of mean observed light intensity.