A 65-year-old male diabetic patient has diplopia worse on upgaze. Ductions are full; however, on upgaze, the left eye only elevates halfway up.His pupils and the remainder of the ocular examination are normal.
What finding would most likely accompany this examination?
|A.||Right upper lid retraction|
Left nystagmus on upgaze
Miotic left pupil
Answer: A. Right upper lid retraction
Explanation: This patient has an isolated superior division of cranial nerve III paresis affecting the left superior rectus and levator palpebrae. The most likely cause for this condition is a diabetic ischemic neuropathy. The weakened levator would cause a left ptosis. He can compensate for this by overstimulating the levator to raise the left lid, consequently raising the right lid higher. Mechanically lifting the left lid will produce a paradoxical right ptosis. The only location at which an oculomotor superior division nerve palsy could occur without affecting additional cranial nerves or the inferior division of cranial nerve III is in the orbital apex. Posterior to the orbital apex, the superior and inferior divisions are joined, and a compressive lesion selective to one division would be very improbable. A unilateral ptosis does not occur with a nuclear lesion.