Ocular myopathies: syndromes with chronic progressive external ophthalmoplegia (CPEO)

Abstract

An ocular myopathy is a degenerative disorder of extra-ocular muscles with the primary site of the lesion in the striated eye muscle cell itself. So ocular myasthenia and orbital thyroid disease are not discussed in this chapter. The clinical picture is dominated by blepharoptosis and restriction of eye movements. The course is usually chronic progressive, so the most important symptom of an ocular myopathy is chronic progressive external ophthalmoplegia (CPEO). This group of diseases is nearly always bilateral, with some asymmetry and asynchrony. Encephalomyopathies with CPEO form a quite distinct and important group. In these the ocular movement disorder can theoretically be ascribed to neuronal disorders as to myopathy of the extra-ocular muscles both. However, in the few autopsies in which data were obtained from the ocular motor nuclei and nerves no pertinent abnormalities were found. Myopathic changes on the contrary were common in the extraocular muscles and other, skeletal, muscles. The interpretation of extra-ocular muscular pathology is however very difficult: ‘myopathic’ changes have been shown to be concomitant with, or the result of chronic denervation [1].