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': 'Gonioscopy is used to study – \nSelect and explain. \nA. Ant. Chamber, B. Post chamber, C. Angle of anterior chamber, D. Retina', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Gonioscopy \n\nOwing to the lack of transparency of corneoscleral junction and total internal reflection of light at the anterior surface of cornea, it is not possible to visualize the angle of anterior chamber directly.\nTherefore, a device (goniolens) is used to divert the beam light and this technique of biomicroscopic examination of the angle of anterior chamber is called gonioscopy.\nIn many conditions such as glaucoma, foreign bodies or tumours, a close inspection of this region is important.', 'role': 'assistant'}]