Anterior ischemic optic neuropathy and dialysis: role of hypotension and anemia

The pathogenesis of anterior ischemic optic neuropathy (AION) primarily inv olves interference with the posterior ciliary artery blood supply to the pr elaminar optic nerve. Uremic patients often have coexisting pathology such as hypotension (decreased blood delivery), or hypertension, atherosclerosis (increased resistance to blood supply), and anemia (low blood oxygen carry ing capacity), predisposing them to AION. We describe a 49-year-old patient on dialysis for many years. He had long-s tanding hypotension, worsened during each dialysis treatment. He awoke one morning at age 48 complaining of blurred vision in the left inferior field. Based on the clinical course, funduscopic and fluorangiographic examinatio n and visual field defects, AION was diagnosed. Nine months after the loss of vision in the left eye, vision in the right eye became blurred and worse ned over the next 24 hours. The diagnosis of AION in the right eye was made . At the last examination ten months later, the patient, still amaurotic, w as given a very poor prognosis for further recovery of the visual defects. Surprisingly, very few cases of AION have been reported in chronic uremic p atients on dialysis: to the best of our knowledge, only 12 including ours. Most of these cases share some features, including hypotension above all an d anemia as common risk factors. Neither the type of dialysis treatment (hemo-, peritoneal dialysis) nor sex seem to have any influence on the occurrence of AION. Uremic children can be affected. What is striking in the three published pediatric cases is tha t they all had polycystic kidney disease. Treatment of AION in all 12 cases consisted of a combination of steroids, i.v. saline, blood transfusions an d rhEpo. AION was more frequently bilateral and irreversible, ending in per manent amaurosis. In conclusion, this study aims to stress that most cases of AION occurring in chronic uremic patients on dialysis have some common f eatures, including hypotension above all and anemia as common risk factors.