KEY POINTS
- Visual loss after anesthesia is a rare, but devastating injury that appears
to occur more frequently after cardiac, spine, and head and neck surgery.
- The causes of postoperative visual loss include central or branch retinal
artery occlusion, anterior and posterior ischemic optic neuropathy, cortical blindness,
and acute glaucoma. Transient visual loss may also occur after transurethral resection
of the prostate and after hysteroscopy.
- Signs and symptoms of visual loss in the postoperative period may be subtle
and can be incorrectly attributed to the residual effects of anesthetic agents.
Any patient complaining of eye pain, an inability to perceive light or motion, complete
or partial loss of visual fields, or decreased visual acuity or who has loss of pupil
reactivity must be immediately evaluated by an ophthalmologist.
- The most common causes of central and branch retinal artery occlusion are
emboli from the operative site and compression of the eye. External pressure on
the eyes must be scrupulously avoided.
- The causes of ischemic optic neuropathy have not been clearly determined.
This disease occurs unpredictably, is multifactorial, and may be related to hypotension,
blood loss, fluid replacement, patient positioning, emboli, the use of vasopressors,
disturbed autoregulation in the optic nerve circulation, anatomic variation in the
optic nerve, and systemic factors in the patient such as hypertension and atherosclerosis.
- Though as yet not proven, patients undergoing operative procedures in the
prone position may be at increased risk for the development of ischemic optic neuropathy.
There is controversy with respect to the appropriate level of blood pressure and
hemoglobin, fluid replacement, and use of vasopressors in these patients. The anesthesiologist
should consider the potential risk for ischemic optic neuropathy in design of the
anesthetic plan and weigh the risks versus benefits of interventions that decrease
blood pressure and hemoglobin concentration in the perioperative period.
- Postoperative visual loss in the presence of focal neurologic signs and/or
the loss of accommodation reflexes or abnormal eye movements suggest a diagnosis
of cortical blindness. Neurologic consultation should be obtained.
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