Abstract
Of 76 children with histiocytosis X 18 had orbital involvement, and four developed additional neuro-ophthalmic complications. No instance of intraocular involvement was detected. Among those patients with ophthalmic involvement the main problems were bilateral or unilateral proptosis, ptosis, papilloedema, optic atrophy, and seventh nerve palsy. Only one patient developed a severe visual defect. Management of the ophthalmological complications depends not only on the extent of the orbital disease but also on the degree of systemic involvement. Overall management by a paediatric oncologist is mandatory.