Lid lag is a clinical finding that may be seen in a number of conditions.
Lid lag: brief interval between the act of looking down and closure of the upper eyelid
Conditions associated with lid lag:
(1) congenital ptosis
(2) hepatic failure
(3) status post ptosis surgery
(4) myopathic disease
(4a) thyrotoxicosis (von Graefe's sign) or excessive intake of thyroxine
(4b) myotonic dystrophia
(4c) familial hyperkalemic periodic paralysis
(5) physiologic lagophthalmos
(6) supranuclear origin (extrapyramidal syndrome)
(6a) congenital supranuclear lid lag
(6b) Guillain-Barre syndrome
(6c) Parkinson's disease
(6d) progressive supranuclear palsy
(7) scarring of the upper eyelid
(8) scalp block (iatrogenic)
(9) myocysticercosis
