Ultrasonic B-scan measurement of the extra-ocular muscles in Graves' orbitopathy.

B-scan real time ultrasonography was performed on a series of controls and patients with thyroidal orbital disease. The thickness of the extraocular muscles was recorded. In the control group the upper value of the 97.5th confidence interval was 0.36 cm. In patients with Graves' orbitopathy the rectus muscle thickness was greater than controls in most. The data suggest that the degree of thickening correlates with the severity of the disease. Muscle thickening in Graves' disease tended to be bilateral and affect both the medial and lateral muscles in each eye.