SLOWLY progressive ptosis and ophthalmoplegia, sparing the pupil was called "progressive nuclear ophthalmoplegia" for many years and was attributed to the degeneration of oculomotor nuclei. It is only since the important papers of Sandifer1 in 1946 and Kiloh and Nevin2 in 1951 that the myopathic origin of this disease has been generally recognized. In several cases, the diagnosis of myopathy has been supported by biopsy of levator palpebrae or one of the recti3-6 and, in a few, by electromyography of ocular muscles.4,7 The most conclusive evidence that the condition is muscular, and not nuclear is provided by autopsied cases of Beckett and Netsky8 and Schwarz and Liu.9 They found no significant abnormalities of oculomotor nuclei or nerves while muscles showed changes compatible with dystrophy.
In this subgroup of muscular dystrophy, the dystrophic process begins in the extraocular muscles with initial complaints of ptosis,
Mathew NT, Jacob JC, Chandy J. Familial Ocular Myopathy With Curare Sensitivity. Arch Neurol. 1970;22(1):68–74. doi:10.1001/archneur.1970.00480190072012