Children with CMC present with blue sclerae, megalocornea, hypoplastic and translucent irides, miosis and high myopia. The lenses may be dislocated as in familial Marfan syndrome but they are often in place and microspherophakic. The clinical history of a boy with CMC is presented. Pathological examination of the eyes showed megalophthalmos with thinned sclera, anomalies of the chamber angle and iris, ill-developed ciliary body and choroid and a small in situ lens.