Chronic progressive external ophthalmoplegia (CPEO) describes an spectrum of hereditary myopathies affecting extraocular muscles (EOMs) commonly manifesting as bilateral ptosis and near total external ophthalmoplegia.
As the name suggests, it is a chronic, progressive, bilateral, typically symmetric, and external (i.e., spares the pupil) ophthalmoplegia. CPEO is associated with mitochondrial disease and can occur as isolated oculomotor symptoms (isolated CPEO) or in conjunction with other systemic findings (“CPEO-plus”). Depending on additional clinical features, CPEO can be evaluated as part of a systemic myopathic or neurologic syndrome
