Abstract:

Monocular elevation deficit (MED) is commonly referred to as double elevator palsy, which is a special type of strabismus. It is divided into three subtypes through etiology and clinical manifestations. Because of their different clinical manifestations, the surgical approach often needs to be tailored. In recent years, to reduce postoperative residual strabismus, the rate of secondary operations and postoperative complications of anterior segment ischemia have been paid more attention. Meanwhile, many researchers have been focused on the continuous improvement and optimization in the surgical methods for MED, gradual development from the initial Knapp operation, including enhanced Knapp, modified Knapp, Jensen, Hummelsheim, Nishida, combined transposition and rectus dissection for MED Ⅲ type and concurrent horizontal strabismus. The latest research progress of surgical methods development in the term of the pathogenesis and clinical manifestations of MED was reviewed, aiming to provide a reference for the clinical design of more appropriate personalized surgery.

Key words: Monocular elevation deficit, Inferior rectus, Superior muscle paralysis, Supranuclear elevation palsy, Ptosis, Knapp′s procedure