Isolated pupil-sparing third nerve palsy.

The challenge in managing patients with pupil-sparing third nerve palsies is met most efficiently by dividing such patients into three groups according to the relative deficits in pupillomotor and extraocular muscle function: (1) patients with a normal pupillary sphincter and completely palsied extraocular muscles. Such patients should not have cerebral angiography if they are aged 50 or more; (2) patients with a normal pupillary sphincter and incompletely palsied extraocular muscles. Such patients should have angiography, particularly if the inferior oculomotor division is spared; (3) patients with a subnormal pupillary sphincter and completely palsied extraocular muscles ("relative pupil-sparing"). Such patients should have angiography unless they have clear-cut vasculopathic findings.