FIGURE 1.

Pathophysiology of microvascular ischaemia. The blood supply to cranial nerves is via an intraneural plexus. There is a blood-nerve barrier. Microvascular abnormalities in diabetics occur due the alterations in the blood-nerve barrier resulting in loss of tight junctions, hypertrophy of the microvascular basement membrane, and loss of microvascular pericytes.8 This may underlie the hyalinzation seen in the post-mortem studies and results in oedema and then hypoxia in the endoneurial space, which causes demyelination and conduction block.5 This prevents salutatory conduction down the axon and paralysis of the extraocular muscles and microvascular nerve palsy. As remyelination occurs, there is complete functional recovery.