Prevalence of graves' orbitopathy in hyperthiroidism

The prevalence of orbitopathy in hyperthyroidism has been a subject of discordance. Endocrinologists often do not consider eyelid retraction as a sign of orbitopathy and ophthalmological series are contaminated by selection biais. Purpose. To estimate the prevalence of ophthalmopathy in a sample of patients with hyperthyroidism followed in a thyroid clinic. Methods. 129 patients with hyperthiroidism, ages from 13 to 08 (mean= 40.84 years) were examined in a cross-sectional design by the same ophthalmologist. For each patient the following data were obtained: a) margin reflex distance for the upper and lower eyelids (upper and lower MRD), Hertel exophthalmometry, alternate cover test, qualitative assessement of diplopia in the diagnostic gaze positions, visual acuity measurement and screening of colour vision with Ishiara color plates. Additional Goldman visual fields and contrast sensitivity testing were obtained respectively in 63 and 33 patients. Results. 84 patients (63.6%) showed some degree of orbitopathy. The majority of these patients presented with eyelid retraction and proptosis (62.2%). Isolated eyelid retraction was seen in 22.2% of the sujects and isolated proptosis in 6.7%. All patients with diplopia (8.9 %) also presented with eyelid retraction and proptosis. Optical neuropathy was diagnosed in 5.5% of the examined eyes. Severe visual loss was seen in just one patient. Conclusions. The estimated prevalence of orbitopathy in Graves' disease depends upon the criterion of orbitopathy and the sensitivity of the method of detection. When eyelid retraction is carefully diagnosed the estimated prevalence is about 60%. Extraocular muscle involvement leading to diplopia (8.9%) and optic neuropathy (5.5%) are less frequent. Severe visual loss is rare (1.2%).