Perioperative visual loss after nonocular surgeries.
OBJECTIVE
To review the current knowledge of persistent visual loss after nonocular surgeries under general anesthesia.


METHODS
Perspective.


METHODS
Literature review.


RESULTS
The incidence of perioperative visual loss after nonocular surgeries ranges from 0.002% of all surgeries to as high as 0.2% of cardiac and spine surgeries. Any portion of the visual pathways may be involved, from the corneas to the occipital lobes, but the most common site of permanent injury is the optic nerves, and the most often presumed mechanism is ischemia. Anterior ischemic optic neuropathy (AION) is more prevalent among cardiac surgery patients and posterior ischemic optic neuropathy (PION) predominates among those who have had spine and neck procedures. Patients range from age five to 81 years and typically awake with severe bilateral visual loss. Multiple factors have been proposed as risk factors for perioperative ION, including long duration in the prone position, excessive blood loss, hypotension, anemia, hypoxia, excessive fluid replacement, use of vasoconstricting agents, elevated venous pressure, head positioning, and a patient-specific vascular susceptibility that may be anatomic or physiologic. However, the risk factors for any given patient or procedure may vary and are likely multifactorial.


CONCLUSIONS
If, when an ophthalmologist is consulted for a patient with perioperative visual loss, an obvious ocular cause is not apparent, urgent neuroimaging should be obtained to rule out intracranial pathology. Anterior and posterior ION should be considered and careful documentation is essential. Currently, the pathogenesis of perioperative ION remains unclear, and preventive and therapeutic measures remain elusive.
Newman
Nancy J
NJ
Department of Ophthalmology, Emory University School of Medicine, Atlanta, Georgia, USA. ophtnjn@emory.edu
D001766:Blindness / Q000209:etiology*; D006801:Humans; D018917:Optic Neuropathy, Ischemic / Q000209:etiology; D011183:Postoperative Complications; D015354:Vision, Low / Q000209:etiology*; D014795:Visual Pathways