Lid lag is the static situation in which the upper eyelid is higher than normal with the  globe in downgaze. It is most often a sign of thyroid eye disease, but may also occur with cicatricial changes to the eyelid or congenital ptosis.
Lid lag describes a specific visual phenomenon where the upper eyelid appears higher than usual when the eye is looking downward. This condition can be caused by various factors, including thyroid eye disease, scarring of the eyelid, or congenital drooping of the eyelid.