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': "Which of the following ophthalmologic condition shows 'vossius ring' during examination? \nSelect and explain. \nA. Corneal ulcer, B. Retinal detachment, C. Traumatic iritis, D. Angle closure glaucoma", 'role': 'user'}, {'content': "Answer: C \nExplanation: In traumatic iritis, the inflammatory cells and flare in the anterior chamber, and finely dispersed cellular keratic precipitates on the corneal endothelium. There may be a 'Vossius ring' on the anterior lens capsule. It is a circular ring of brown pigment which occurs due to striking of the contracted pupillary margin against the crystalline lens. It is always smaller than the size of the pupil. Ref: Augsburger J.J., Correa Z.M. (2011). Chapter 19. Ophthalmic Trauma. In P. Riordan-Eva, E.T. Cunningham, Jr. (Eds), Vaughan & Asbury's General Ophthalmology, 18e.", 'role': 'assistant'}]