Anesthesia can cause vision problems, though the risk during most surgeries is extremely low. Estimates for perioperative visual loss after non-eye surgeries range from about 1 in 8,000 procedures overall to roughly 1 in 500 for high-risk spine operations. The more common eye-related issue is corneal abrasion from the eyelids drifting open during general anesthesia, which is uncomfortable but usually heals on its own. Rarer and more serious outcomes include damage to the optic nerve, blocked blood flow to the retina, and even cortical blindness from stroke-like events in the brain’s visual centers.
How Common Is Perioperative Vision Loss?
The overall incidence of vision loss after non-eye surgery sits around 0.013%, meaning it affects roughly one in every 8,000 patients. That number climbs considerably for certain procedures. Spine surgery carries the highest risk, with estimates around 0.03% for ischemic optic neuropathy alone. Cardiac surgery follows closely, with about 0.086% of patients affected by the same condition.1British Journal of Anaesthesia. Perioperative visual loss and anaesthesia A large analysis of U.S. hospital records from 1998 to 2012, looking at over 2.5 million spinal fusion discharges, found about 1 case of ischemic optic neuropathy per 10,000 operations and a similar rate for retinal artery occlusion.2PubMed Central. Perioperative Visual Loss in Spine Fusion Surgery: Ischemic Optic Neuropathy in the United States from 1998 to 2012 in the Nationwide Inpatient Sample
To put these numbers in context, the risk after something like an appendectomy is vanishingly small, about 0.0012%. It’s the long, complex operations involving major blood loss or unusual body positioning where the danger rises enough to matter clinically.1British Journal of Anaesthesia. Perioperative visual loss and anaesthesia
Ischemic Optic Neuropathy
The most common serious cause of vision loss linked to anesthesia and surgery is ischemic optic neuropathy, which happens when the optic nerve doesn’t get enough blood and oxygen. It comes in two forms depending on which part of the nerve is affected. The anterior type has been reported most often after cardiac surgery, while the posterior type shows up more frequently after spine operations and radical neck surgeries.3PubMed Central. Perioperative visual loss in ocular and nonocular surgery
The posterior form is better understood mechanistically. The optic nerve needs both an adequate blood supply and enough oxygen-carrying capacity in the blood. When a patient loses a lot of blood during surgery, the remaining blood is diluted with replacement fluids, which drops its ability to deliver oxygen. If blood pressure also falls or the pressure around the eye’s tissues rises, the nerve gets squeezed from both directions: less oxygen in the blood and less blood reaching the nerve. That combination can starve the nerve of oxygen long enough to cause lasting damage.4PubMed Central. Posterior ischemic optic neuropathy: Perioperative risk factors Clinical data consistently link this complication with intraoperative anemia, sustained low blood pressure, substantial blood loss, large-volume fluid administration, and pre-existing vascular disease that limits the body’s ability to regulate its own blood flow.5PubMed Central. Perioperative Visual Loss After Spine Surgery: A Case-Based Review of Posterior Ischemic Optic Neuropathy
Why Prone Positioning Raises Eye Pressure
Many spine surgeries require the patient to lie face down for hours, and this position alone creates significant stress on the eyes. A meta-analysis of studies measuring intraocular pressure in prone adults found that pressure inside the eye rises sharply within the first ten minutes of being placed face down and continues climbing throughout the duration of prone positioning.6PubMed Central. Systematic Review and Meta-Analysis of Prone Position on Intraocular Pressure in Adults Undergoing Surgery The same effect occurs during laparoscopic surgery when the patient is tilted steeply head-down, because gravity shifts fluid toward the head and eyes.7PubMed. Increase in intraocular pressure is less with propofol than with sevoflurane during laparoscopic surgery in the steep Trendelenburg position
Elevated eye pressure over many hours can compromise blood flow to the retina and optic nerve. Even protective eye coverings can backfire. In one reported case, a patient developed central retinal artery occlusion during prone spine surgery while wearing foam-padded eye-protection goggles; the device itself likely exerted enough pressure on the eye to block blood flow.8Anesthesia & Analgesia. Visual Loss in a Prone-Positioned Spine Surgery Patient with the Head on a Foam Headrest and Goggles Covering the Eyes: An Old Complication with a New Mechanism In another case, a teenager undergoing a seven-hour scoliosis repair in the prone position woke up with proptosis, severely elevated eye pressure, and central retinal artery occlusion in one eye, all traced to external compression during the long operation.9PubMed. Central retinal artery occlusion and ophthalmoplegia following spinal surgery in the prone position
Corneal Abrasions During General Anesthesia
The most frequent eye complaint after general anesthesia isn’t dramatic vision loss but corneal abrasion, a scratch on the surface of the eye. Under general anesthesia, the muscles that keep the eyelids shut relax, and up to 59% of patients develop some degree of incomplete eyelid closure. Combined with reduced tear production and the loss of the protective reflex that normally rolls the eyeball upward during sleep, the cornea can dry out and get scratched by surgical drapes, oxygen masks, or simple air exposure. When incomplete closure goes unnoticed, rates of surface eye inflammation have been reported as high as 27 to 44%.10Anesthesia and Pain Medicine. Comparison of eye protection methods for corneal abrasion during general anesthesia
The good news is that most corneal abrasions heal within a few days with lubricating drops or ointment. They’re painful and annoying, and they can cause blurred vision and light sensitivity in the short term, but permanent damage is uncommon. The takeaway for patients is that a scratchy, watery eye in the first day or two after surgery under general anesthesia is not unusual and is almost always treatable.
Nitrous Oxide and Intraocular Gas Bubbles
This is one of the more alarming interactions in anesthesiology and catches some patients off guard. After certain retinal surgeries, surgeons place a gas bubble inside the eye to hold the retina in position while it heals. The gases used, typically sulfur hexafluoride or perfluoropropane, can remain in the eye for weeks or even months. If a patient with a remaining gas bubble undergoes a second surgery that uses nitrous oxide as part of the anesthetic, the nitrous oxide diffuses into the bubble faster than the existing gas can diffuse out. The bubble expands rapidly, spiking intraocular pressure high enough to cut off blood flow through the central retinal artery.11British Journal of Anaesthesia. Use of nitrous oxide causing severe visual loss 37 days after retinal surgery
The result can be irreversible blindness in the affected eye.12PubMed Central. Nitrous oxide anaesthesia in the presence of intraocular gas can cause irreversible blindness In at least one published case, this happened 37 days after retinal surgery, when the patient may not have realized any gas was still present. This is why patients who have had retinal procedures involving gas injection often wear a medical alert bracelet and are instructed to tell any future anesthesia team about the gas. If you’ve ever had vitreoretinal surgery, bring it up every single time you go under anesthesia, even months later.
Drug-Triggered Acute Glaucoma
Some medications used during anesthesia can dilate the pupil, and in people whose eyes have a specific anatomical vulnerability, pupil dilation can trigger acute angle-closure glaucoma. This happens when the dilated iris physically blocks the drainage pathway for fluid inside the eye, causing pressure to spike abruptly. Case reports have documented this after intravenous atropine, scopolamine, and ephedrine, all drugs occasionally given during the perioperative period.13JAMA Ophthalmology. Acute Angle-Closure Glaucoma Associated With Surgical Anesthesia
Acute angle-closure glaucoma causes sudden eye pain, nausea, blurred vision, and seeing halos around lights. It requires emergency treatment to lower the pressure, usually with eye drops and sometimes laser therapy. The risk is concentrated in people with naturally shallow anterior chambers in the eye, a trait more common in older adults and people of East Asian descent. If you know you have narrow drainage angles, mentioning this to your anesthesiologist before any surgery is worthwhile.
Cortical Blindness
A completely different mechanism can cause blindness even though the eyes themselves are fine. Cortical blindness occurs when the visual processing areas at the back of the brain are damaged, usually by a stroke or an embolism during surgery. In these cases, the patient’s eyes respond normally to light, and an eye exam looks unremarkable, but the person cannot see. It has been reported after complicated general anesthesia, particularly in older patients, and may be related to small blood clots or air emboli reaching the brain’s visual cortex.14PubMed Central. Cortical blindness after complicated general anesthesia in urological surgery Recovery from cortical blindness varies widely, and some patients regain vision partially or fully over weeks to months, while others do not.
Complications from Regional Eye Blocks
When anesthesia is injected directly around the eye for eye surgery (a retrobulbar or peribulbar block), the injection itself carries risks that include retrobulbar hemorrhage, injury to the optic nerve, puncture of the eyeball, and even occlusion of retinal blood vessels. In rare cases, the anesthetic can track along tissue planes to reach the brainstem, causing confusion, breathing problems, and even temporary blindness in the opposite eye.15PubMed Central. Contralateral amaurosis after a retrobulbar block
Retrobulbar hemorrhage is especially dangerous for patients on blood-thinning medications. In a review of roughly 160,000 records, three cases of severe retrobulbar hemorrhage were identified, and all involved patients on dual antiplatelet or anticoagulation therapy. The visual outcomes were poor: one patient ended up with substantially reduced vision and two lost all light perception permanently.16PubMed. Dual platelet inhibition in cases of severe retrobulbar hemorrhage following retrobulbar and peribulbar anesthesia Modern techniques using ultrasound guidance and sub-Tenon’s blocks have reduced the incidence of these complications, though they have not eliminated them entirely.
Temporary Visual Disturbances After Waking Up
Not every vision complaint after anesthesia signals real eye damage. Ketamine, a drug sometimes used alongside general anesthetics, is well known for causing altered perceptions as patients emerge from sedation. These can include vivid visual disturbances, a sense of being outside one’s body, and dream-like imagery.17PubMed Central. Subanaesthetic ketamine and altered states of consciousness in humans A meta-analysis found that patients who received ketamine had about 1.5 times the rate of hallucinations compared to those who did not.18PubMed Central. Effect of Ketamine on Postoperative Neurocognitive Disorders: A Systematic Review and Meta-Analysis These effects are transient, typically clearing within hours, and do not indicate structural damage to the eyes or visual pathways.
Similarly, some regional nerve blocks in the neck and shoulder area can temporarily affect the eye on one side. Interscalene nerve blocks, used for shoulder surgery, commonly cause Horner’s syndrome, a combination of a drooping eyelid, a constricted pupil, and decreased sweating on the same side of the face. This happens because the local anesthetic spreads to the nearby sympathetic nerve chain.19PubMed Central. Horner’s Syndrome Caused by Ultrasound-Guided Supraclavicular Nerve Block It looks alarming but resolves as the block wears off, usually within hours.
Who Faces the Highest Risk?
The risk factors for perioperative vision loss are numerous and tend to stack. Long duration in the prone position, excessive blood loss, low blood pressure, anemia, large-volume fluid replacement, and the use of blood-vessel-constricting drugs have all been implicated. Elevated venous pressure in the head, specific head positioning, and an individual patient’s unique vascular anatomy or pre-existing vascular disease further contribute.20PubMed Central. Perioperative visual loss after nonocular surgeries Microvascular diseases like diabetes and hypertension appear to limit the eye’s ability to regulate its own blood flow, making patients with these conditions more vulnerable when surgical stresses pile up.21PubMed Central. Perioperative vision loss: A complication to watch out
No single factor reliably predicts which patient will lose vision. The literature consistently describes this as a multifactorial problem, meaning the likelihood rises as more risk factors combine in a single operation. A healthy young person having a short surgery in a standard position faces an almost negligible risk. A middle-aged patient with diabetes undergoing an eight-hour spinal fusion with significant blood loss is in a very different category.
What Surgical Teams Do to Prevent It
Prevention starts with eliminating direct pressure on the eyes. For prone surgeries, pin-based head holders that cradle the skull by its outer bone rather than by the face effectively avoid any contact with the eyes and surrounding structures.22PubMed Central. Perioperative visual loss following prone spinal surgery: A review Beyond head fixation, anesthesia teams monitor blood loss and try to avoid prolonged low blood pressure and severe anemia. Periodic checks of the eyes during long prone cases, staged surgeries to limit time in the prone position, and careful fluid management all form part of the evolving standard of care.
The challenge is that no single preventive measure has been definitively proven to eliminate the risk, partly because the condition is so rare that randomized trials would need enormous numbers of patients. Several specialized head-positioning devices have been developed to reduce ocular compression, but current designs don’t yet allow anesthesiologists to monitor facial pressure points in real time during surgery.23Neurosurgical Focus. Current intraoperative devices to reduce visual loss after spine surgery For corneal abrasions, the standard approach is taping the eyelids shut or applying lubricating ointment at the start of anesthesia.
Legal and Consent Considerations
Vision loss after surgery generates a disproportionate share of malpractice claims relative to its rarity, likely because the consequences are life-altering. An analysis of legal cases from 2007 to 2016 found that every identified claim involving perioperative vision loss resulted in permanent injury. About three-quarters of those cases involved spine surgery, and nearly 90% involved prone positioning. Over half the patients said they had not been warned about the possibility of vision loss before the operation. When documentation was reviewed, two-thirds of cases showed improper or missing records. Settled cases averaged roughly $900,000 in payouts.24PubMed. A contemporary medicolegal analysis of perioperative vision loss from 2007 to 2016
For patients, the practical lesson is straightforward: if you are scheduled for a long surgery, especially one performed in the prone position, ask your surgeon and anesthesiologist directly whether vision loss is a recognized risk for your procedure. It should appear on the consent form for high-risk operations. The fact that more than half of claimants said they were never told suggests this conversation still doesn’t happen as consistently as it should.25Journal of Clinical Review & Case Reports. Perioperative Visual Loss Following Transanal Endoscopic Microsurgery in Prone Position: Medico Legal Consideration You’re not being difficult by asking about it. You’re being informed.