The preferential involvement of extraocular muscles by myasthenia gravis

Abstract

Extraocular muscles are preferentially involved by myas-thenia gravis, affecting nearly all patients during the course of the illness. Ocular manifestations of ptosis and diplopia may be the sole abnormality in 10–15% of patients. The anatomical and physiological properties of ocular muscles appear to form the primary basis of their susceptibility compared to other skeletal muscles. The autoimmune process differs among patients with ocular myasthenia and may contribute to the limitation of symptoms to the ocular muscles. This review highlights the unique properties of extraocular muscles and the levator palpebrae in order to provide insights in the involvement of these muscles by myasthenia gravis.