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': 'In specular microscopy endothelial density is measured by? \nSelect and explain. \nA. Optical doubling, B. Fixed frame analysis, C. Optical focusing, D. None', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Fixed frame analysis Endothelial cell density in specular microscopy is counted by fixed frame analysis and variable frame analysis. Cell density (ceIlsimrn2 ) = Cell count in frame", 'role': 'assistant'}]