Gas vs Silicone Oil in Retinal Surgery – What’s the Difference?

Why do we use gas or oil in retinal surgery?

In many retinal surgeries, especially:

• Retinal detachment repair, and
• Macular hole surgery

We need something inside the eye that acts as a tamponade, a bubble that presses gently against the retina from the inside.

This helps to:

• Keep the retinal tear dry and flat while the laser or freezing treatment seals it
• Hold the edges of a macular hole together while it heals

To create this internal support, we commonly use either:

• Gas, or
• Silicone oil

Gas in retinal surgery: types and how long they last

There are several types of gas we can use:

• Air
• SF₆
• C₂F₆
• C₃F₈

They differ mainly in how long they stay in the eye:

• Air: ±5–10 days (often about a week)
• SF₆: ±14–16 days
• C₂F₆: ±4 weeks
• C₃F₈: ±6–8 weeks

We will choose the gas based on how long the retina or macular hole needs support.

How does gas behave in the eye?

After vitrectomy, we fill the eye with a gas bubble. Over time:

• The gas is gradually absorbed
• The eye continuously produces its own clear fluid
• As the gas shrinks, it is replaced by fluid

What you experience:

• At first, vision is very blurry, and you can’t see clearly through a gas bubble
• You may see a moving line or “horizon” as the gas shrinks and the fluid level rises
• Because the image on the retina is inverted, you often see the fluid line at the top of your vision moving downwards as the bubble gets smaller
• Eventually, the gas bubble disappears completely, and the eye is full of clear fluid

You effectively rely on your other eye for most vision while the gas is in place.

Pros of gas

• Self-absorbing, no second operation is needed to remove it
• Excellent tamponade for many routine retinal detachments and macular holes
• Widely used and well understood

Major con of gas: travel and altitude

Gas inside the eye is very sensitive to pressure changes, just like a packet of chips that expands as you drive up a mountain pass.

If you:

• Fly in an airplane, or
• Go to a much higher altitude (mountains, high passes)

The gas bubble can expand, causing a dangerous rise in eye pressure. This can lead to:

• Severe pain
• Risk of damage to the optic nerve or retinal blood vessels

Because of this:

You may not fly or change altitude significantly while gas is in your eye until your eye specialist confirms it is safe.

Silicone oil in retinal surgery

Silicone oil is another internal tamponade option used in more complex situations.

We often choose oil for:

• Complex retinal detachments
• Re-detachments (eyes that have detached again after prior surgery)
• Cases with significant scar tissue (PVR)
• Multiple retinal breaks or complicated tears
• Situations where the patient must travel or fly soon after surgery

How does silicone oil behave in the eye?

• Silicone oil does not get absorbed
• It stays in the eye at a relatively constant volume
• It provides a long-term, stable tamponade

Patients can generally:

• See through oil better than through gas, especially once the eye has settled
• Vision isn’t perfect; it’s not as clear as normal fluid, but it is often good enough to navigate and function

Pros of silicone oil

• Stable does not shrink like gas
• You can fly and change altitude safely
• Helpful for patients who need to return overseas quickly (for example, tourists who develop a retinal detachment while visiting the Kruger National Park and must fly back home)
• Provides a strong, long-lasting tamponade for complex retinal problems

Main con of silicone oil: it must be removed

Unlike gas, oil does not disappear on its own.

• A second surgery is usually needed later to remove the oil, once the retina is stable
• If left too long, oil can sometimes cause:
  • Raised eye pressure
  • Emulsification (breaking into small droplets)
  • Other long-term issues in some cases

That said, with appropriate timing and follow-up, silicone oil remains a very safe and useful option in experienced hands.

Positioning after surgery: why it matters more with gas

After retinal detachment or macular hole surgery, your retinal surgeon may ask you to position in a specific way:

• Left side
• Right side
• Face-down
• Or another specific head position

Why?

• Gas floats inside the eye
• We want the gas bubble to press exactly where the retinal tear or macular hole is
• Correct head positioning helps the gas support the right area

As the gas bubble gets smaller, precise positioning often becomes even more important because there is less gas to cover the target area.

This can be challenging for some patients, especially if they are asked to position for 10–14 days.

With silicone oil:

• The oil fills the eye more completely and does not shrink
• Positioning is often less critical (though your surgeon’s instructions still matter)
• This can be another advantage of oil in certain patients

So, which is better, gas or oil?

There is no “better” option; it depends on:

• The type and complexity of your retinal detachment or macular hole
• Whether you’ve had previous retinal surgery
• Presence of scar tissue (PVR) or multiple tears
• You need to travel or fly
• How well you can manage post-operative positioning
• Your overall eye health and medical situation

In simple terms:

• For routine retinal detachments and standard macular hole surgery, we often prefer gas.
• For complex detachments, re-detachments, significant scarring, or patients who must fly or change altitude, we often choose silicone oil.

We will discuss these options with you and explain why a specific choice is best for your eye.

Final thoughts

Hearing that gas or silicone oil will be put into your eye can sound intimidating, but these tools are a crucial part of modern retinal surgery and have allowed many patients to keep or regain useful vision.

Key points to remember:

• Gas:
  • Self-absorbs over days to weeks
  • Excellent for many standard cases
  • No flying or major altitude changes until cleared
  • Vision is very blurred while gas is present

•  Silicone oil:
  • Stays in place until surgically removed
  • Better for complex cases and when travel is essential
  • You can typically fly and drive over passes safely
  • Allows for more functional vision in the early period

If you’ve been advised to have retinal surgery in Mbombela, Nelspruit or the wider Mpumalanga region and have questions about gas vs oil, make a list and bring it to your consultation. Understanding the plan helps you feel more confident and prepared for the road to recovery.