A large choroidal metastasis was diagnosed in the right eye of a 44-year-old man referred for admission to hospital because of 'retinal detachment.' At the same time in the second, symptomless, eye a very small metastasis was observed. Close follow-up during the next month showed an extremely rapid deterioration of visual acuity and visual field in this eye. This is thought to be characteristic of such metastatic tumours in contrast to the slower progress of choroidal malignant melanoma. The application of local radiotherapy to the same eye led to an impressive improvement in the visual acuity and visual field. The source of these bilateral choroidal metastases, which was found only after the patient's death, proved to a bronchial carcinoma.