When a person experiences vertical double vision or vision in which one image seems to be rotated with respect to the other, the most likely cause is a fourth cranial nerve (CN IV) palsy. The most common causes are trauma and vascular. The forth nerve is very susceptible to trauma, especially frontal blows to the head which throw the brain forward within the cranium. This happens during injuries like going over the handle bars of a bicycle after a sudden stop and landing on the forehead, or running into a wall.
Unexplained forth nerve palsy in a child should prompt consideration of cerebellar tumors.
Examination of a person with a fourth cranial nerve, (CN IV) palsy shows the eye higher on the involved side than on the other.
The superior oblique…show more content… A patient with alternating ptosis, a drooping eyelid that is present one day in the right eye and the next day in the left eye is almost certainly myasthenia. An episode of double vision from a single muscle or one that gets worse when the person is tired may be myasthenia. Having the person look up for a long time will test for myasthenia because the lid will begin to sag after a few seconds. Repeating the test again and again will shorten the time before the lid drops. A definite diagnosis can be made by doing the Tensilon (edruphonium) test. In myasthenia, the acetylcholine neurotransmitter is metabolized too rapidly.
Tensilon blocks the acetylcholine esterase that destroys the acetylcholine, allowing the muscle to contract better. If the patient has myasthenia gravis, the eye movement problem will improve with Tensilon.
The treatment of ocular nerve palsies depends on the underlying disease. Traumatic nerve injuries often regenerate. The injured nerve grows out through the sheaths of the dead nerves at a rate of about one centimeter per month. This translates to six to twelve months in most cases. Since the paralysis will go away when the nerve regenerates, surgery to move the eyes is not