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.