Lid Lag (PPT)

The classical eye signs of thyroid associated ophthalmopathy (TAO) of Graves' Disease is illustrated by case ID925-4. This 50 year old woman with TAO is included in the collection because she illustrates very well lid lag (persistent elevation of the upper eyelid in downgaze) - von Graefe sign Eyelid position is coordinated with vertical eye movements. In upgaze the lids elevate. In downgaze the lids typically relax and follow the globe down and close. In TAO, in addition to patients with dorsal midbrain lesions (ID 921-1, 924-2 and 925-4) the normal relationship is impaired and the eyelids remain elevated while the eyes move down. The presence of lid-lag in downgaze without significant lid retraction in primary gaze suggests a separate central mechanism for the control of the upper eyelid on downgaze. Galetta et al suggests that one possible lesion for lid-lag without retraction involves the inhibitory connection from the supranuclear downgaze centers to the central caudal nucleus. In addition this patient had 1.Minimal bilateral exophthalmos 2.Slight reduction of orbital resilience 3.Congested scleral blood vessels 4.Slight limitation of upgaze 5.Absent Bell's reflex (eyes fail to move up under closed lids consistent with a restrictive orbitopathy and tethering of the globe inferiorly) Neuro-ophthalmological examination was otherwise completely normal and ruled out compression of the optic nerve by enlarged extraocular muscles crowding the orbital apex. CT Orbit The inferior rectus and medial rectus muscles were enlarged. The scan confirmed the diagnosis of TAO. See also: http://content.lib.utah.edu/cdm/ref/collection/ehsl-shw/id/333