Cranial mononeuropathy III - diabetic type
Cranial mononeuropathy III -- diabetic type -- is usually a complication of diabetes that causes double vision and eyelid drooping .
Diabetic third nerve palsy; Pupil-sparing third cranial nerve palsy
Causes, incidence, and risk factors
Cranial mononeuropathy III - diabetic type is a mononeuropathy , which means that only one nerve is damaged. It affects the third cranial (oculomotor) nerve, which is one of the cranial nerves that controls eye movement.
This type of damage may occur along with diabetic peripheral neuropathy . Cranial mononeuropathy III is the most common cranial nerve disorder in people with diabetes. It is due to damage to the small blood vessels that feed the nerve.
Other causes may include:
- Double vision
- Drooping of one eyelid (ptosis)
- Pain in the head or behind the eye
Signs and tests
An examination of the eyes will determine whether only the third nerve is affected or if other nerves have also been damaged. Signs may include:
- Eyes that are not aligned (dysconjugate gaze)
- Pupil reaction that is almost always normal
Your health care provider will do a complete examination to determine the possible effect on other parts of the nervous system. Depending on the suspected cause, you may need:
You may need to be referred to a doctor who specializes in vision problems related to the nerves in the eye (neuro-ophthalmologist).
There is no specific treatment to correct the nerve injury.
Treatments may include:
- Close control of blood sugar levels
- Eye patch or glasses with prisms to reduce double vision
- Pain medications
- Surgery to correct eyelid drooping or eyes that are not aligned
Some people may recover without treatment.
Many patients get better over 3 - 6 months, although some have permanent eye muscle weakness.
- Permanent eyelid drooping
- Permanent vision changes
Calling your health care provider
Call your health care provider if you have double vision and it doesn't go away in a few minutes, especially if you also have eyelid drooping.
Control of blood sugar levels in people with diabetes may reduce the risk of developing this disorder.
Baloh RW. Neuro-ophthalmology. In: Goldman L, Ausiello D, eds. . 23rd ed. Philadelphia, Pa: Saunders Elsevier;2007:chap 450.