The gas bubble after retinal surgery: positioning, travel, anesthesia, and what not to do

After retinal surgery, patients open their eye to strange vision: as if looking through water, or seeing a horizontal line that moves whenever they move their head. Then come many instructions: "Do not fly," "Sleep on your side," "Tell any anesthesiologist." And the questions follow: Why all these instructions? For how long? What happens if I don't follow them? These instructions are not routine; some of them protect the eye from serious complications that can be completely prevented. In this article we explain the reason behind each one.

Why does the surgeon put gas in the eye?

In operations such as retinal detachment repair and macular hole closure, the retina needs something to press on it from the inside for a while, until the tear or hole heals. So at the end of a vitrectomy, the surgeon fills the eye with a gas bubble. The bubble always floats upwards, so it presses on whatever part of the eye is uppermost, and stops fluid leaking under the retina while it heals (Neffendorf et al., 2018).

The gas does not stay forever. The eye absorbs it gradually, and it is replaced by the natural fluid the eye produces.

How long does the gas stay in the eye?

That depends on the type of gas and its concentration, which the surgeon chooses according to the case. In a study measuring how gases disappear after surgery, ordinary air lost half its volume in about a day and a half, whereas sulfur hexafluoride (SF6) took about 3 days and perfluoropropane (C3F8) about 6 days to lose half its volume, in eyes that still had their natural lens (Thompson, 1989). Because the gas shrinks gradually in this way, a small bubble can remain for much longer than these figures.

What matters in practice: ask your surgeon which gas is in your eye, and find out when it is expected to have gone completely, because the instructions below apply until the last bubble has disappeared.

What is vision like with gas in the eye?

At first vision is very poor, because the gas fills most of the eye. As it is absorbed, a horizontal line appears that moves and wobbles with head movement: gas above it, fluid below it. The patient begins to see through the part below the line. Over time the line gradually moves down, then the bubble becomes a small circle moving in the lower part of the vision, and then it disappears.

This is completely normal. What deserves a call to the doctor is severe pain, or a new curtain appearing after vision had been improving.

Why are flying and high altitudes not allowed?

Because gas expands when the air pressure around it falls, and the eye is a closed space that cannot stretch. If the gas expands, the pressure in the eye rises sharply, and blood may stop reaching the retina and optic nerve.

In an experiment in which patients were placed in a chamber simulating aircraft cabin pressure, eye pressure doubled on average during the ascent in those whose eye contained gas filling only about 10–15% of it, while the pressure did not change in the other eye (Mills et al., 2001). These results supported the usual advice not to fly with gas in the eye (Mills et al., 2001). Specialist hospitals advise against flying or traveling to high altitudes until the gas has gone completely (Moorfields Eye Hospital NHS Foundation Trust, 2020).

The risk is not limited to aircraft. Doctors described four patients whose eye pressure rose sharply after they drove up about 750 to 1,100 meters after surgery; they improved with treatment (Brosh et al., 2014). So tell your surgeon before any trip that involves going up to a high area, even by car.

Why must the anesthesiologist be told?

Because nitrous oxide, sometimes used in general anesthesia, enters the gas bubble in the eye quickly, making it expand and raising the eye pressure sharply. In a series of patients who had general anesthesia with this gas while their eyes contained a gas bubble from earlier surgery, four out of five ended up with very poor vision, and three of them lost all light perception (Fu et al., 2002).

So the researchers recommended avoiding this gas entirely during anesthesia while there is gas in the eye, and suggested that patients wear a wristband alerting any medical team to the gas, in case they need emergency surgery and cannot speak (Fu et al., 2002). Specialist hospitals advise telling the anesthesiologist before any operation (Moorfields Eye Hospital NHS Foundation Trust, 2020).

Positioning after surgery: why, and how necessary is it?

Because the bubble floats upwards, the surgeon sometimes asks for a particular head position, so that the bubble presses on the right place: on the tear in a retinal detachment, or on the center of the macula for a macular hole.

The scientific evidence here is less conclusive than many patients think:

• After repair of a retinal detachment that involved the macula: a review of clinical trials found that face-down positioning straight after surgery may reduce displacement of the retina after it heals, which sometimes causes distortion of lines and double vision. But it may increase the chance of raised eye pressure, and the evidence is of very low certainty (Fung et al., 2024).
• After macular hole surgery: another review found that face-down positioning may have little or no effect on hole closure, and that the evidence is of low certainty (Cundy et al., 2023). We explain this in our article on macular hole.

What does this mean for you? Your surgeon decides the position and how long to keep it according to where the problem is, its size and the type of gas, and this may differ from one patient to another. So follow their instructions, and ask clearly: Which position? How many hours a day? For how many days? Am I allowed to sleep on my back?

Questions patients often ask

When can I fly?

Once your surgeon has confirmed at an examination that the gas has gone completely (Moorfields Eye Hospital NHS Foundation Trust, 2020). Do not rely on the number of days alone, or on your own feeling that the bubble has gone.

Can I see normally while the gas is there?

No; vision through gas is poor. It improves gradually as the gas is absorbed, but final vision depends on the original disease and the state of the retina.

I need emergency surgery somewhere else. What should I do?

Tell the medical team immediately that you have gas in your eye, and its type if you know it, so that any anesthetic gas that could react with it is avoided (Fu et al., 2002).

Is it different with silicone oil?

Yes. Oil is not absorbed and usually needs an operation to remove it after several months, and it has its own instructions (Moorfields Eye Hospital NHS Foundation Trust, 2020). We explain it in our article on silicone oil in the eye.

Summary

The gas bubble is an important tool that helps the retina heal after surgery, but it carries risks that can be completely prevented if the patient knows about them: flying, high altitudes and some anesthetic gases can make it expand and raise eye pressure dangerously. Positioning after surgery differs from case to case, and the evidence is not always conclusive, but following the surgeon's instructions remains the foundation. Know which gas is in your eye, and carry that information with you until it has gone completely.

This information is for health education and does not replace a medical examination.