Ischemic optic neuropathy: are we any further?

Postoperative vision loss (POVL) as related to spinal surgery and the prone position has garnered increasing attention in the US over the last 15 years, resulting in an increase of litigations submitted to the legal system. It might be associated with the development of new surgical techniques involving complex instrumentation of the spine. By 2000, the magnitude of this problem was such that the American Society of Anesthesiologists developed a Postoperative Visual Loss Registry in an effort to better understand and evaluate this devastating operative complication.

The cause of ischemic optic neuropathy (ION) as the most complex entity of POVL is still unclear. Retrospective studies show that although it can strike patients of any age, there is an increased incidence in patients less than 18 and more than 65 years of age. Significant risk factors include male sex, anemia, surgery lasting over 6 h, and intraoperative hypotension. Profound anatomical knowledge and new animal studies have helped to define possible mechanisms underlying ION.

ION is still poorly understood and risk factors remain speculative. Given that there is no known treatment, increased understanding should help to prevent this postoperative complication.