It is a myopathy characterized by slowly progressive paralysis of the elevator eyelid, orbicularis oculi, and extraocular muscles, manifests mainly in adults, and can be permanently isolated. However, in a few cases it is associated with skeletal myopathy, predominantly affecting the axial or proximal muscles, causing abnormal fatigue and even permanent muscle weakness. In this case, the condition is still referred to as isolated progressive external ophthalmoplegia.

Treatment: There is no effective treatment and ptosis improves with tarsorrhaphy correction surgery as a palliative measure.