The presence of developmental dysplasia of the retina.

Persistence of the hyaloid artery, which is the embryonic artery that runs from the optic disc to the posterior lens capsule may persist; the site of attachment may form an opacity. The hyaloid artery is a branch of the ophthalmic artery, and usually regresses completely before birth. This features results from a failure of regression of the hyaloid vessel, which supplies the primary vitreous during embryogenesis and normally regresses in the third trimester of pregnancy, leading to a particular form of posterior cataract.