Glossary term
Ptosis
Reference only — not medical advice. See disclaimer.
The drooping or falling of the upper eyelid due to weakness or dysfunction of the levator muscle or its nerve supply, which may partially or completely obstruct vision and cause a tired or asymmetric appearance. Surgical correction (ptosis repair) involves tightening or repositioning the levator muscle and is distinct from blepharoplasty, which addresses excess skin rather than muscular function.