This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Neuro Ophthalmology, Subject name: Ophthalmology
[{'content': 'All of them are true about Optokinetic Nystagmus (OKN) EXCEPT \nSelect and explain. \nA. Jerk nystagmus induced by moving repetitive targets, B. Useful for localising cause of isolated homonymous hemianopia, C. Slow phase is a pursuit, fast phase is saccade, D. Type of pathological nystagmus', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Optokinetic nystagmus It is a physiological jerk nystagmus ( not pathological) Useful in localizing cause of an isolated homonymous hemianopia. Induced by presenting to gaze the objects moving serially in one direction, such as strips of a spinning optokinetic drum. The eyes will follow a fixed strip momentarily and then jerk back to reposition centrally to fix up a new strip. Similar condition occurs while looking at outside things from a moving train. note- - Saccade are Rapid jerky conjugate eye movements,to direct the fovea to a target as the gaze shifts from one object to another Contralateral frontal lobe initiates it & Flocculus(Lobule IX of cerebellum) controls it. - Pursuit is slow tracking eye movements to direct target on fovea.Ipsilateral parieto-occipital lobe controls it & Fastigial nuclei initiates it', 'role': 'assistant'}]