Two types of cortical cataract were observed in senile Wistar rats: posterior subcapsular (PSC) and supranuclear (SNC). The beginning of PSC was denoted clinically by vacuole accumulation in the posterior suture. The appearance of vacuoles, granules and cloudiness spread laterally in all directions, maintaining a primarily superficial cortical distribution. Microscopic comparison of rat and human forms showed the opacity to represent subcapsular accumulations of fluid and cytoplasmic residues, generated by the swelling and disintegration of basal extremities of fiber cells. The clinical onset of murine SNC was usually represented by small vacuole accumulation in the anterior cortical suture system. Later, lamellar separations formed in the outer cortex, followed by the development of water clefts in the deeper cortex. Microscopically, advanced forms showed extensive swelling and coalescence of cortical fibers, associated with Morgagnian globules and myelin figures.