Iris Colobomas

Iris colobomas are defects occurring in of any/all layers of developing iridal tissue, as a result of inappropriate embryonic differentiation. Coloboma(s) located within the iridal body may result in the false appearance of multiple pupillary opening or “pseudpolycoria”. The complete absence of iris tissue (termed “aniridia”) is rare. Clinically, most iris colobomas typically appear as “notch” defects within the iris. Commonly affected breeds include the Australian Shepherd & Collie breeds.