Sagittal magnetic resonance imaging of dysthyroid ophthalmopathy.

Sagittal magnetic resonance imaging (MRI) scans of the eye and orbit were made of 30 eyes in 15 cases of dysthyroid ophthalmopathy (DO). On the basis of these scans, we sought to elucidate relationships between the morphological condition of the levator palpebrae muscle, fatty tissue in the upper eyelid and the superior, inferior recti muscles and the occurrence of such symptoms as lid retraction, lid swelling and vertical disturbance of eye movement. The levator palpebrae muscle was enlarged in all 15 DO eyes (100%) with upper eyelid retraction. In 16 (88.9%) of 18 eyes with apparent lid swelling, enlargement of the preaponeurotic fat or submuscular fat pad was clearly evident. In the control eyes, no such enlargement was seen in either the levator palpebrae muscle or orbital fatty tissue. The clear space between the superior recti and the levator palpebrae muscles that was seen in control eyes was absent in all five eyes that presented a disturbance in infraduction. In 8 (80%) of 10 eyes with a disturbance in supraduction, the inferior rectus muscle was enlarged and muscle extension was impaired. Sagittal MRI seemed to be a useful means of obtaining a better clinical understanding of a variety of eye symptoms associated with DO.