Reduction in visual acuity due to orbital metastasis is rarely the first sign of lung cancer and very few cases have been published in the literature. Here we report a rare case of lung adenocarcinoma with orbital metastasis as the first presenting sign. The incidence of primary tumors that metastasize to the orbit is approximately 7%. In 19% of the cases, there is no history of cancer when the patient presents with ophthalmic symptoms, and in 10%, the primary site remains obscure despite intensive systemic evaluation. Our patient showed a partial improvement in vision after successful combination of chemotherapy and radiotherapy. Blurred vision due to orbital metastasis as the primary symptom of lung cancer is very uncommon. A great index of suspicion is essential when an orbital lesion appears.