Chronic Progressive External Ophthalmoplegia (CPEO)
Chronic Progressive External Ophthalmoplegia (CPEO), also known as ocular myopathy, is characterized by the gradual weakening of the eye muscles. The main symptom of CPEO is ptosis, which is the drooping of one or both eyelids. As the condition progresses, individuals may need to lift their chin or use their forehead muscles to lift their eyelids in order to see. The muscles responsible for moving the eye from side to side are also affected, requiring affected individuals to turn their head to look around.
In addition to eye muscle weakness, CPEO can lead to other symptoms such as difficulty swallowing (dysphagia), overall muscle weakness, impaired muscle coordination, movement issues, hearing loss, loss of sensation in the limbs, and even depression. While most cases of CPEO are inherited, it is possible for individuals with no family history of the condition to develop it.
Understanding Internuclear Ophthalmoplegia (INO)
Internuclear Ophthalmoplegia (INO) is a condition that affects the nerves responsible for controlling horizontal eye movements, while leaving vertical eye movements unaffected. There are three types of INO: unilateral, which impacts one eye; bilateral, which affects both eyes; and wall-eyed bilateral, where both eyes turn outward.
The underlying cause of INO is damage to the medial longitudinal fasciculus (MLF), a bundle of nerve fibers located between the third and sixth cranial nerves in the brainstem. This damage is often attributed to an artery blockage or injury to the protective covering surrounding the nerve fibers.
One of the common symptoms of INO is diplopia or double vision. In older adults, strokes are typically the primary cause of INO, and it often manifests as a unilateral condition. On the other hand, younger adults with multiple sclerosis may develop bilateral INO. Additionally, certain infectious diseases such as tuberculosis, AIDS, brucellosis, cysticercosis, and syphilis can also lead to the development of INO.