Pneumosinus dilatans as the aetiology of progressive bilateral blindness.

Pneumosinus Dilatans is a rare condition of the craniofacial skeleton which was diagnosed in an adolescent male who presented with progressive bilateral blindness and many features of osteodysplasty (Melnick-Needles Syndrome). The clinical course and unusual pathology of this case which included the compression of both optic nerves within long tubes of bone are described, together with the surgical intervention performed to arrest the patient's loss of vision.