A 65-year-old patient presented with increasing loss of vision in the right eye. A relative afferent pupillary defect as well as visual field perimetry deficits in an otherwise unremarkable eye led to the presumed diagnosis of ischemia of the optic nerve; however, further imaging revealed an extensive necrotic bronchial carcinoma in the left upper lobe metastasizing to the orbit with compression of the optic nerve. The clinical and histological features are discussed with respect to possible primary origins of orbital metastases.