Capecitabine is an orally administered fluoropyrimidine carbamate antineoplastic agent, widely used to treat different tumor types. Eye toxicity is not well established with this type of drug. Here, we report the case of a 57-year-old man with a low rectal cancer whose vision decreased 3 weeks after starting a daily treatment of capecitabine and radiotherapy. After eliminating all other diagnoses, toxicity of antineoplastic agents remains the most likely hypothesis, making it the first case of vision loss induced by this capecitabine.