SummaryThe clinical features of many apparently widely differing syndromes may be explained on common grounds. It is not suggested that they have a common cause. The vascular malformation of the retina present in Von Hippel's disease is responsible for changes in the fundus which resembles those seen in Coate's disease. In early childhood they lead to the so‐called infantile form of that disease and, in infancy, to one of the forms of pseudo‐glioma.When the inflammation involves the ciliary body and iris, the picture of a chronic cyclitis with the formation of a membrane, and its harmful effect on the lens, is superadded. This is the picture which is seen to appear in the premature infant born with a normal fundus and which gradually develops a “retro‐lental fibroplasia.” Retrolental fibroplasia is a retinitis associated with an irido‐cyclitis occurring in the i