Vision loss after non-ocular surgery is a rare but potentially devastating surgical complication that is usually the result of cortical blindness, ischemic optic neuropathy or retinal vascular occlusion. Due to its rare and unexpected occurrence, the origin of perioperative vision loss (POVL) is poorly understood.
Today at the Annual Meeting of the American Society of Anesthesiologists, researchers from the University of Chicago introduced the largest and most comprehensive examination to date of the rate of POVL in the United States, examining the prevalence rate for a 10-year period from 1996 to 2005.
"It has been widely speculated by clinicians that the rates of POVL are on the rise," said presenting study author Steven Roth, M.D. "Previous studies reporting on POVL rates have been small or confined to single institutions. To gain a more detailed account of POVL rates in this study we used the Nationwide Inpatient Sample (NIS) to evaluate the prevalence of POVL in the eight most commonly performed operative procedures in the U.S., including cardiac and spine surgery."
Researchers retrospectively studied the NIS from 1996 to 2005 in a stratified sample of approximately 20 percent of U.S. community hospitals. Among 5,679,422 eligible discharges examined through the NIS database, 1326 contained a diagnosis code for POVL with a rate of 2.35/10,000. The eight surgeries evaluated in the analysis were hip/femur surgery, knee replacement, gallbladder removal, cardiac surgery, appendectomy, colon resection, laminectomy without fusion and spinal fusion.
The analysis revealed that the overall incidence of POVL per 10,000 cases decreased from 3.06/10,000 in 1996-1997 to 2.03/10,000 in 2004-2005. Similar trend for decreases over time was evident for cardiac surgery from 9.74/10,000 in 1996-1997 to 8.30/10,000 in 2004-2005. For spinal fusion there was a greater decrease in POVL over time from 6.30/10,000 in 1996-1997 to 2.79/10,000 in 2004-2005.
For specific diagnoses over all procedures, prevalence of ischemic optic neuropathy (ION) and cortical blindness (CB) were not found to decrease over time, but retinal vascular occlusion (RVO) did decline from 2.07/10,000 in 1994-1996 to 1.31/10,000 in 2004-2005.
Refuting speculation, the analysis found that the prevalence for vision loss occurring after the most commonly performed operative procedures in the U.S. has decreased between 1996 and 2005. In all procedures examined, rates of POVL were found to occur more often in cardiac and spinal fusion surgery. Patients younger than 18 years old had the highest risk of POVL due to an increased risk of cortical blindness, while patients older than 50 were at higher risk for ION and RVO.
"Whether these findings reflect changes in anesthetic and surgical practice requires further study, however the trend for decreased rates of POVL in all categories is reassuring for clinicians and also for patients entering the operating room," concluded Dr. Roth. "Although encouraging, these results should not be interpreted as suggesting a need for decreased vigilance. It is the vigilance of anesthesiologists and all clinicians in the operating room that leads to improvements in patient safety and satisfaction."