A congenital type of cataract with opacities along the Y sutures of the fetal lens nucleus; usually does not affect vision. The Y sutures are an important landmark because they identify the extent of the fetal nucleus. Lens material peripheral to the Y sutures is lens cortex, whereas lens material within and including the Y sutures is nuclear. At the slit lamp, the anterior Y suture is oriented upright, and the posterior Y suture is inverted. Any insult (eg, infectious, traumatic, metabolic) to the nuclear or lenticular fibers may result in an opacity (cataract) of the clear lenticular media.