TYK322
The most common cause of postoperative visual loss (POVL) is
a) Central retinal artery occlusion
b) Ischemic optic neuropathy
c) Cortical blindness
d) Direct orbital compression
e) Conjunctival/lid edema
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The most common cause of postoperative visual loss (POVL) is
a) Central retinal artery occlusion
b) Ischemic optic neuropathy
c) Cortical blindness
d) Direct orbital compression
e) Conjunctival/lid edema
Answer b. Significant edema may ensue during long cases in the prone position, but this is unlikely to lead to blindness (although it may cause transient blurriness). According to the ASA Postoperative Visual Loss Registry, ischemic optic neuropathy was associated with 83 cases and central retinal artery occlusion with 10 cases. Risk factors for ischemic optic neuropathy cases were higher anesthetic duration, blood loss, and increased percentage of patients with bilateral disease compared with central retinal artery occlusion cases. Ischemic optic neuropathy also occurred in patients with their heads suspended in the air via Mayfield pins, demonstrating that it can occur in the absence of pressure on the globe. None of the cases of central retinal artery occlusion occurred using Mayfield pins.