Orphanet rare-disease nomenclature id Orphanet_891 (Familial exudative vitreoretinopathy) (FEVR) is a rare hereditary vitreoretinal disorder characterized by abnormal or incomplete vascularization of the peripheral retina leading to variable clinical manifestations ranging from no effects to minor anomalies, or even retinal detachment with blindness. Also known as: Criswick-Schepens syndrome, FEVR.