[Progressive external ophthalmoplegia: clinical observations in two cases (author's transl)].

Two patients developed Progressive External Ophthalmoplegia at the age of 20 and 50 years respectively. There was no clinical invovlement of either skeletal muscles or the CNS. Electron microscopy of the lateral rectus muscle showed in one case regressive changes in the myofibrillary apparatus and in the mitochondria. Light microscopy of the quadriceps muscle in the other case showed only mild non-specific myopathic changes. EMG of the ocular muscles suggested a primary muscular damage in both cases.