Overview
What is Microvascular Cranial Nerve Palsy?
It is the most common cause of double vision in persons older than 50 years of age.
Movement of our eyes is controlled by 6 muscles. These muscles receive signals from nerves called cranial nerves (CN) III, IV and VI. These tiny nerves have a blood supply (in the form of small arteries) running on their surface.
When the blood supply is compromised, it results in weakness or paralysis of the muscles such that the 2 eyes now do not work together simultaneously. This is called a microvascular cranial nerve palsy, and results in double vision.
Causes
It is believed that as we get older, we are more prone to blockage of the small arteries because of hardening of the arteries (called atherosclerosis). Atherosclerosis is associated with:
1. Binocular double vision
This means that the patient will see double if both eyes are used together. If he or she covers either eye, there will not be any double vision.
In CN III palsy:
In CN IV palsy:
In CN VI palsy:
2. Pain
What are the signs?
When observing the 2 eyes, you may notice that the affected eye is unable to move in one or more directions in severe cases. In milder cases, there will be incomplete movement or slowing of the eye movement.
Detection & Treatment
What can I do about it?
The majority of microvascular cranial nerve palsies recover on their own within 4 – 12 weeks without any residual double vision. Presently, there is no known medication or treatment to hasten the recovery process.
However, the main problem is to diagnose it correctly and not to miss more serious problems, such as tumours and a brain stroke which may be life-threatening and require urgent treatment.
What can be done to relieve the double vision?
1. Patching
2. Prisms
Care Management
What is the outlook for this condition?
The outlook for this condition is excellent with the majority of patients experiencing a complete recovery. Occasionally the condition may recur in the same eye or the other eye.
Specialties & Services
