The present disclosure relates to a computer-readable storage medium storing instructions that can cause a processor to process image data defining an image of a vascular structure of temporal vascular arcades of a retina to estimate a location of the fovea of the retina in the image by transforming received image data such that the vascular structure in the image defined by the transformed image data is more circular than the vascular structure defined by the image data； calculating, for each of a plurality of pixels of the transformed image data, a respective local orientation vector indicative of the orientation of any blood vessel present in the image； calculating a normalized local orientation vector for each of the pixels； operating on an array of accumulators； and estimating the location of the fovea in the image of the retina using the location of a pixel of the transformed image data.
