ABSTRACT
OBJECTIVE: The aim of this article was to investigate the structural basis of ocular motility and visual abnormalities in humans with congenital fibrosis of the extraocular muscles (CFEOM). METHODS: 17 volunteers from 2 CFEOM pedigrees Clinical ophthalmic and motility examed and 18 normal control subjects were correlated with thin-sectioned magnetic resonance imaging (MRI) across the orbit and the brain-stem level. RESULTS: Subjects with CFEOM had severe bilateral blepharoptosis, limited supraduction, and variable ophthalmoplegia. In affected subjects, MRI demonstrated atrophy of the levator palpebrae superioris, all EOMs, and the optic nerves, and small or absent orbital motor nerves. The oculomotor nerve was most severely hypoplastic, but the abducens was also affected. Subjects with CFEOM exhibited subclinical but highly significant reduction from normal in mean optic nerve size (P < 0.05). There are also some difference between the two CFEOM pedigrees. CONCLUSIONS: These findings suggest that neuronal disease is primary in CFEOM, with myopathy arising secondary to abnormal innervation and the oculomotor nucleus and trochlear nucleus of the abnormalities defects.
