An 8-year-old boy presented to the ED with Two weeks of fatigue Three days of double vision Ptosis Painless periorbital swelling of the left eye His medical history was unremarkable with no recent weight loss, travel, or trauma. Examination His visual acuity without correction was 20/20 OU. His right pupil was 3.5 mm and briskly reactive, while the left pupil was 8.5 mm and unreactive to light or near effort; there was no relative afferent pupillary defect. Results of testing with the use of an Amsler grid and Ishihara color plates were within normal limits.
The visual fields were full to confrontation. The optic nerves and retina were normal in both eyes. Further examination was notable for left periorbital swelling, proptosis, and moderate ptosis of the upper eyelid. His extraocular motility examination demonstrated severe ophthalmoparesis of the left eye: 0% supraduction, 20% normal…
