A brother and sister, the only two children of non-consanguineous parents, have bilateral microphthalmos, degenerative corneal opacities, shallow anterior chambers, and in the anterior vitreous white masses like cotton wool with some large blood vessels. Excision of the mass from the vitreous cavity of one eye showed surprisingly normally developed detached retina round a core of fibrous condensed vitreous. Otherwise the children are normal and have the normal male and female karyotype.A very similar sibship has been reported by Franceschetti (1956) -a brother and sister, children of first cousins, being affected; the consanguinity of these parents supports our suggestion that a recessive inheritance explains the abnormalities in our cases. No evidence of heredity exists in the similar case described by Magnus (1927) or in the group of possibly similar cases of "retinal dysplasia" without systemic involvement described by Reese & Straatsma (1958), but our cases may well belong to the same category; also, our cases may represent examples of an extreme form of "falciform retinal folds".