Persistent pupillary membranes (PPMs) are embryonic residues of neural-crest origin. During the embryonic life, the pupillary membranes have the role of feeding the developing lens but they lose this function when the aqueous humour is produced. Normally, few weeks after birth, the pupillary membranes undergo atrophy. Alterations of this process and its continuous persistence are responsible of pathological events. The manifestations of PPMs vary from iris residues to fibrous filaments that attach to the lens or cornea (dysplastic pupillary membranes). For rare cases that need therapeutic intervention, medical therapy or, very rarely, surgery are required. The breeds mainly predisposed to this disease are for dogs:
Basenji, Chow Chow, Petit Basset Griffon Vendeen, English Cocker Spaniel, while for cats: the Bengal, Birman and Persian. This article describes the clinical manifestations of PPM and the breeding advice in the different clinical conditions.