Collier's sign

Collier's sign (also known as Collier's tucked lid sign[1] or posterior fossa stare[2]) is bilateral or unilateral eyelid retraction.

It is an accepted medical sign of a midbrain lesion, first described in 1927 by J Collier.[3] With the eyes in the primary position, the sclera can be seen above the cornea, and further upgaze increases the distance between the eyelids and irises.[4] Causes include upper dorsal midbrain supranuclear lesions such as Parinaud's syndrome, 'top of the basilar syndrome',[2] midbrain infarction, neurodegeneration or tumour, multiple sclerosis, encephalitis, and Miller-Fisher syndrome.[5] The cause is thought to be damage to the posterior commissure levator inhibitory fibres[2] which originate in the M-group of neurons.[4]