Cranial mononeuropathy III is a complication of diabetes that leads to double vision and eyelid drooping.

Cranial mononeuropathy III - diabetic type is a mononeuropathy, which means that only one nerve is damaged. It involves the third cranial (oculomotor) nerve, which is one of the cranial nerves that controls eye movement. This type of damage is usually associated with diabetic neuropathy.

Cranial mononeuropathy III is the most common cranial nerve disorder in diabetics.

• Double vision, abrupt onset
• Drooping of one eyelid
• Pain in head or behind eye

An examination of the eyes will show various patterns of eye movement to determine whether only the third nerve is affected or if other nerves have also been damaged. Often, the gaze is dysconjugate (eyes are not aligned). Pupil reaction may or may not be normal. Sometimes eye pain is also reported.

In some cases, it may not be clear if the nerve damage is due to diabetes or some other cause such as an aneurysm. In some cases, a lumbar puncture and/or angiogram may be necessary to rule out other causes.

There is no specific treatment to correct the nerve injury. Close control of blood sugar levels may help. Surgery may be needed to correct eye lid drooping or dysconjugate gaze. Often, an eye patch can reduce double vision and analgesics (pain medications) may be needed to treat pain. Some people may recover without treatment.

The outcome varies. Many patients eventually recover, although some have permanent eye muscle weakness.

• Permanent vision changes
• Disfigurement, permanent eyelid drooping

Call your health care provider if double vision is present and not relieved in a few minutes, especially if eye lid drooping is also present.

Control of blood sugar levels in people with diabetes may reduce the risk of developing this disorder.