Sudden unilateral visual loss in children is usually caused by a complication of acute purulent sinusitis. Differential diagnosis must include malignant tumours of the orbit or the paranasal sinuses involving the optic nerve. Rapid and adequate diagnostic measures are required in this emergency situation. In comparison, acute or progressive bilateral blindness is a very rare disorder.

We report two cases of bilateral visual loss caused by malignant tumours and diagnostic and therapeutic strategies are described. Our reports show that these life-threatening disorders and their severe complications can be managed successfully if well-coordinated interdisciplinary cooperation is conducted from the beginning. If surgery is performed in this vulnerable region, it may be facilitated by computer-aided modelling techniques. During the last decade the prognosis for rhabdomyosarcoma and malignant lymphoma, the most frequent mesenchymal tumours of childhood, has improved dramatically. Thus, any loss of time causing a delay in correct diagnosis and the onset of adequate therapy must be avoided. Intensive cooperation with paediatric oncologists has to be enlisted from the beginning to avoid unnecessary, repetitive, invasive, or imaging diagnostics and to accelerate the onset of specific therapy.