Adult-onset chronic progressive external ophthalmoplegia with mitochondrial myopathy (CPEO-MM) is a rare genetic disorder that affects the muscles of the eyes and other parts of the body. It is caused by mutations in the mitochondrial DNA, which is responsible for energy production in cells. Symptoms include progressive weakness and paralysis of the muscles that control eye movement, as well as muscle weakness and fatigue in other parts of the body. Other symptoms may include hearing loss, vision problems, and difficulty speaking. Treatment is focused on managing symptoms and may include physical therapy, medications, and dietary changes.