Diminished vision due to choroidal metastasis as the first manifestation of lung carcinoma is rare. Here, we report a case of a 22-year-old non-smoker man, with no known medical illness presented with painless loss of vision in the right eye for one month, which became painful after two weeks. The anterior segment examination of the right eye revealed an anteriorly subluxated crystalline lens with angle-closure glaucoma secondary to a retrolental choroidal mass. Prompt assessment and investigation revealed right eye choroidal metastasis secondary to small cell carcinoma. The right eye responded well to chemotherapy evidenced by a reduction of intraocular pressure and size of the choroidal mass. It is crucial to have a high index of suspicion to exclude non-ocular primary tumours as probable causes in any choroidal masses.