The syndrome of chronic progressive external ophthalmoplegia has been generally regarded as denoting an ocular myopathy. Recent evidence is presented, however, which both denies the universality of a myopathic etiology and demonstrates our present inability to distinguish between myopathy and neural weakness of ocular muscles.
Daroff RB. Chronic Progressive External OphthalmoplegiaA Critical Review. Arch Ophthalmol. 1969;82(6):845-850. doi:10.1001/archopht.1969.00990020837022