This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Ophthalmology
[{'content': 'Lamina cribrosa is absent in - \nSelect and explain. \nA. Morning glory syndrome, B. Nanophthalmia, C. Colobama of retina, D. Optic nerve agenesis', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The nerve fibers forming the optic nerve exit the eye posteriorly through a hole in the sclera that is occupied by a mesh-like structure called the lamina cribrosa. It is formed by a multilayered network of collagen fibers that inse into the scleral canal wall. It is absent in morning glory syndrome. Ref khurana 6/e', 'role': 'assistant'}]