Vitrectomy explained

Keyhole surgery to remove the vitreous gel

Vitrectomy is an operation to remove the vitreous, the clear gel that fills the back of the eye. It is done through very small openings in the white of the eye, so it is a form of keyhole surgery, and it is usually carried out as a day case under either local or general anaesthetic. Once the gel has been removed, the space is filled with fluid, or sometimes with a gas bubble or, occasionally, silicone oil, depending on what the eye needs.

It is a common and well-established operation. What follows explains the main reasons it is done, and the one or two things that matter most if you are ever to have it.

It treats several different problems at the back of the eye

Vitrectomy is used for a range of conditions. One of the most frequent reasons is to repair a retinal detachment, where the retina has lifted away from the wall of the eye and needs to be put back into place. Another is to clear a vitreous haemorrhage, which is bleeding into the gel that has not cleared on its own, often related to diabetes or to a torn retinal blood vessel.

It is also used to treat certain problems at the macula, the central part of the retina, such as a membrane growing on its surface or a small hole within it. Much more rarely, it is used to treat a serious infection inside the eye. And in a small number of carefully selected cases, it is used to remove floaters that are genuinely disabling.

The most definitive option, but held in reserve

When vitrectomy is used for floaters, it is the most definitive option, because removing the gel removes the floaters within it. But it is reserved for the few people whose floaters seriously affect daily life, precisely because it is surgery on an otherwise healthy eye and carries real risks. For most people, floaters are best left alone or, occasionally, considered for laser. You can read how the choice is made on the floater treatment options page.

Sometimes a gas bubble is left to support the retina

For some conditions, particularly a retinal detachment or a macular hole, the surgeon fills the eye with a gas bubble at the end of the operation. The bubble presses gently on the retina and holds it in the right position while it heals. Over the following days to weeks the gas is slowly absorbed and replaced naturally by the eye's own fluid, so it does not need to be removed.

Different gases last for different lengths of time, from a week or two for a short-acting gas to several weeks for a longer-acting one. While the bubble is present your vision in that eye is very blurred, and you may be asked to hold your head in a particular position for a time to keep the bubble where it is needed. Your surgeon will explain which gas you have and what is expected of you.

The one rule to remember: do not fly with gas in the eye

If you have a gas bubble in your eye, you must not fly, and you must avoid high altitude such as mountain travel, until the bubble has completely gone. The reason is simple. As you go up, the surrounding air pressure falls, and the gas bubble expands in response. In the enclosed space of the eye, that expansion can drive the pressure inside the eye up to dangerous levels, which can cut off the blood supply to the retina, threaten your sight, and cause severe pain.

Your surgeon will tell you when the gas has fully absorbed and it is safe to fly again, and you will usually be given a wristband to wear that warns others that there is gas in your eye. Until you are given the all-clear, treat the no-flying rule as absolute.

Certain anaesthetic gases can make the bubble expand

There is a second, less well-known reason to make sure everyone knows you have gas in your eye. If you need any other operation while the bubble is still present, the anaesthetist must be told, because certain anaesthetic gases, in particular nitrous oxide, pass into the bubble and make it expand quickly. Just as with flying, that expansion can raise the pressure in the eye sharply. Always tell any doctor, dentist, or anaesthetist that you have a gas bubble in your eye until you have been told it has gone.

Recovery takes weeks, and the operation carries real risks

Recovery takes place over several weeks, and vision usually improves gradually as the eye settles and any gas absorbs. As with any operation, there are risks. In an eye that still has its natural lens, a cataract will almost always develop in the months or years afterwards and often needs its own operation. There is a small risk of a new retinal tear or detachment, of raised pressure or bleeding, and a rare but serious risk of infection inside the eye.

For conditions like retinal detachment or a troublesome vitreous haemorrhage, the benefits of vitrectomy clearly outweigh these risks. For floaters alone, that balance is very different, which is why in the UK vitrectomy is not offered routinely for floaters, and is considered only when they are genuinely disabling.