[Two cases of unexplained pupillary dysfunction after cardiac surgery in severely diabetic patients]

We experienced two cases of unexplained pupillary dysfunction in severely diabetic patients after cardiac surgery. In both patients, marked bilateral dilatation of the pupils and the absence of light reflex were recognized immediately after leaving the operating room. The pupillary dysfunction, however, was not accompanied by other neurological deficits, and the pupil sizes returned normal spontaneously by 24 hours. We speculated that impaired peripheral perfusion during cardiopulmonary bypass caused transient tissue ischemia on the basis of microangiopathies of severe diabetes mellitus. Bilateral ciliary ganglia were thought to be most susceptible to the impaired perfusion and responsible for the pupillary dysfunction.