Mysterious Episodes of Mary
Episode III
Mary had always felt that her "night driving vision" had deteriorated with age, and she had become more and more uncomfortable on the road at night. One night while driving home from a local PTA meeting. she noticed that when stopped at an intersection, she would experience double vision when looking to the right to check for traffic. Her vision looking left and forward appeared to be unaffected, but the double vision was troublesome. Over the next few days, the problem appeared to get worse,and her husband noticed that her right eye appeared to be turned slightly inward when she looked strait ahead. Mary made an appointment with the ophthalmologist who was able to schedule her the following week. Over the next couple of days, Mary noticed that the vision in her left eye started to blur. Her ophthalmologist examined both eyes and reported that the two problems she was experiencing appear to be unrelated. The double vision when looking right was found to be caused by cranial nerve palsy. The problem with the left eye was not immediately diagnosed, and further neurological testing was recommended. As with her previous episodes, her visual symptoms began to diminish over time.
Question
How many cranial nerves are involved in eye movements? Which are they?