This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Investigation in ophthalmology and miscellaneous topics, Subject name: Ophthalmology
[{'content': 'This is used in diagnosis of: \nSelect and explain. \nA. Steropsis, B. Colour vision, C. Refractive error, D. Strabismus', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The above image shows Titmus fly test used for diagnosis of stereopsis.', 'role': 'assistant'}]