Thyroid eye disease

A 53-year-old woman presented with subacute, progressive, painless, bilateral vision loss over the previous six months. Past medical history was significant for hypertension, hyperlipidemia, and Graves disease that was well controlled on propylthiouracil (PTU). She was an active smoker of one pack per day (PPD) of cigarettes with a total 35-pack-year history. Best-corrected vision was 20/300 in the right eye (OD) and 20/400 in the left eye (OS). External exam demonstrated bilateral proptosis (Fig. 8.1), with Hertel exophthalmometer measurements of 27 mm in both eyes (OU). Pupils were 5 mm in the dark and 3 mm in the light OU, with no relative afferent pupillary defect (RAPD). Extraocular movements demonstrated a bilateral, right greater than left global ophthalmoplegia. Intraocular pressures were elevated bilaterally at 28 mmHg OD and 25 mmHg OS. Automated visual fields (Humphrey 24-2) demonstrated bilateral central/cecocentral scotomas (Fig. 8.2). External examination demonstrated periorbital erythema and edema, as well as upper and lower lid retraction. Slit lamp biomicroscopy showed moderate conjunctival injection, and inferior corneal punctate epithelial erosions OU. Dilated fundus exam demonstrated a cup-to-disc ratio of 0.2 with bilateral temporal optic nerve atrophy (Fig. 8.3). Magnetic resonance imaging (MRI) of the brain and orbit without contrast was performed at an outside institution just prior to evaluation, which demonstrated proptosis and enlarged extraocular muscles with sparing of the tendinous sheaths OU and compression of the optic nerve at the orbital apex bilaterally (Fig. 8.4).