The invention relates to a system and method for measuring light diffusion in the eyeball or eye region, by recording and processing retinal images. The inventive system includes a double-pass ophthalmoscopic system having means for correcting low-order aberrations. Said system can be used to record images of the plane of the retina on a CCD camera, the outer part of said images containing information relating to ocular scattering. The aforementioned images can be used to obtain the objective scattering index (OSI), providing the ratio between the energy on the outer part of the image and the energy in the central part, or, alternatively, the modulation transfer function (MTF) area can be used for this purpose once the low frequencies have been filtered. According to the inventive method, the low-order aberrations are corrected before a retinal image or a temporal sequence of retinal images is captured and recorded.