In an extremely rare case, a 32-year-old woman experienced sudden blindness in one eye and occasional flashes of light in the other. Doctors initially found nothing wrong with her eyes, but further examination revealed a large, whitish-yellowish mass growing in the back of her right eye and fluid accumulation under the retina. A similar, smaller lesion was also found in her left eye. Blood tests ruled out viral infection and blood disorders, and an X-ray and whole-body scan revealed a cancerous mass in her right lung that had spread to multiple organs, including the choroid layer of her eyes. Cancer that spreads from one body part to another is called metastasis. When cancer spreads to the eyes, the migrating tumors lodge themselves into the choroid, but this is rare in lung cancers, occurring in only about 1% of cases. It’s even more unusual for patients to experience visual impairment as the first sign of underlying lung cancer, with only a handful of such cases reported in medical literature. The woman’s case is particularly unusual because she was a non-smoker, and cigarette smoking is the primary risk factor for lung cancer. The doctors who treated her believe her case could be the first example of a non-smoking woman of her age developing visual impairment as the first symptom of lung cancer. They speculate that she may have a distinct subset of lung cancer that can spread without causing telltale symptoms of metastasis. After her cancer was diagnosed, the woman was referred to an oncologist for treatment. More research is needed to ensure that this seemingly specific type of lung cancer is promptly diagnosed and treated in other people.