This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Ophthalmology
[{'content': "Amsler's grid is used to evaluate ? \nSelect and explain. \nA. Central 10 degress of vision, B. Central 20 degrees of vision, C. Peripheral vision, D. Lens opacity", 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Central 10 degress of vision Metamorphopsia is a phenomenon wherein the patient perceives objects to have an altered, irregular contour or shape. For example, graph paper lines may be bent or obscured in areas. This can be reviewed for any changes over time using an Amsler grid, which tests the central 10deg of vision. It is associated with diseases affecting the macula such as central serous choroidopathy, age- related macular degeneration, diabetic macular oedema and macular hole.", 'role': 'assistant'}]