Macula precise localization using digital retinal angiographies

The fovea is a spot located in the center of the macula, and responsible for sharp central vision. In this paper a method to detect the macula location and size is presented, as a first step towards the fovea location. Prior to the macula detection, the optic disk size and position is computed. This is performed through the combination of two stages: firstly, a clustering algorithm is used to select the regions which contain the pixels with the highest gray levels. A correlation filter is applied to these regions to compute the approximate center of the optic disk. Then, in order to extract the optic disk, a deformable model which is used. Then, following the morphological properties of the eye, the macula location and size is determined by means of a new correlation filter. Search with this filter is performed in a reduced area of interest, whose size and position is determined by means, again, of the morphological properties of the eye. The algorithm has proven to be fast and accurate in the set of test images, composed by 135 digital retinal images, where the tests have been performed by comparing our results with those obtained by two expert clinicians from two different hospital centers.