You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is A mother brought her six years old child to Eye OPD with history of night blindness. She told that the baby suffered from measles 6 months ago. Examination revealed corneal scarring. The doctor should suspect deficiency of and explain in detail?
None