Paretic thyroid myopathy.

Reports of vertical deviation in Graves' disease in recent years have always been associated with restrictive phenomena and positive forced duction testing, usually related to a tight inferior rectus. Two cases of medically proven Graves' diseased of ten-year duration are presented with increasing vertical disparity. Forced duction testing showed no restriction. Saccadic velocity tests using electro-oculography confirmed paresis of the inferior rectus in both cases. No cases of "true" vertical extraocular muscle paresis in chronic Graves' disease have been reported in the American literature.