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': 'Intractable secondary glaucoma is seen in – \nSelect and explain. \nA. Diffuse iris melanoma, B. Nodular iris melanoma, C. Melanocytic deposits in anterior part of iris, D. Melanocyte proliferation in posterior uveal tissue', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Iris melanomas may be of two types :-\n\nCircumscribed/ Nodular: - It is the most common type which presents as a pigmented spot on the iris. Glaucoma is less common and usually treatable.\nDiffuse iris melanoma: - Present as a unilateral dark iris (hyperchromic hetrochromia). The tumor has diffusely infiltration pattern of growth and invades the intertrabecular spaces, and plugs the drainage mechanism. This results in intractable secondary glaucoma.', 'role': 'assistant'}]