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

Diabetic third nerve palsy; Pupil-sparing third cranial nerve palsy

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 usually occurs with diabetic neuropathy.

Cranial mononeuropathy III is the most common cranial nerve disorder in people with diabetes.

• Double vision that comes on quickly
• Drooping of one eyelid
• Pain in head or behind eye

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)
• Normal or abnormal pupil reaction

In some cases, it may not be clear if the nerve damage is due to diabetes or some other cause, such as an aneurysm. Tests to rule out other causes may include:

• Computed tomography (CT) angiogram
• Lumbar puncture
• Magnetic resonance angiography (MRA)

There is no specific treatment to correct the nerve injury.

Treatments may include:

• Close control of blood sugar levels
• Eye patch or prisms to reduce double vision
• Pain medications (analgesics)
• Surgery to correct eyelid drooping or eyes that are not aligned

Some people may recover without treatment.

Many patients get better over time, although some have permanent eye muscle weakness.

• Permanent eyelid drooping
• Permanent vision changes

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.