Cataract surgery - Risks of cataract surgery

The risk of serious complications as a result of cataract surgery is very low. Most common complications are treatable and don't have a long-term impact on your vision.

The risk of complications is higher in people with other eye conditions, such as uveitis, high myopia (severe short-sightedness) or diabetic retinopathy.

The risk of complications is also higher if you cannot lie flat easily, have problems breathing or are taking tablets for prostate problems.

Ask your eye surgeon (ophthalmologist) to explain the possible risks before your operation.

Cloudy vision

The main problem that can occur after cataract surgery is a condition called posterior capsule opacification (PCO).

This is where part of the lens capsule (the "pocket" that the lens sits inside) thickens, which can cause cloudy vision. This is not the cataract returning, but a skin or membrane growing over the back of the artificial lens.

Less than 10% of people who have cataract surgery will eventually develop PCO, usually within two years.

If you develop PCO and your vision is affected, you may need laser eye surgery (when laser light is used to cut through the membrane) to correct it. During this procedure, the cloudy part of the lens capsule will be removed, leaving enough of the capsule to hold the artificial lens in place.

Laser eye surgery for PCO is a short and relatively simple procedure that normally takes about 15 minutes. Your vision should either be improved immediately or within a few days and, as no surgical incisions or stitches are necessary, you should be able to return to your normal activities straight away.

Other complications

Other complications of cataract surgery are much less common, but can include those listed below. 

During the operation:

• inability to remove all of the cataract
• tearing of the lens capsule
• bleeding inside the eye
• a bit of the cataract dropping into the back of the eye
• damage to other parts of the eye, such as the cornea (the transparent outer layer of the eye)

After the operation:

• inflammation (swelling and redness) in the eye
• swelling of the retina (cystoid macular oedema) – where fluid builds up between layers of the retina at the back of the eye, sometimes affecting vision
• swelling of the cornea – where fluid builds up in the cornea at the front of the eye; this usually clears itself
• retinal detachment – a rare complication where the retina (layer of nerve cells inside the back of the eye) becomes separated from the inner wall of the eye
• infection in the eye, such as endophthalmitis (a rare bacterial infection)

You should seek immediate medical advice if you experience any loss of vision or increasing pain or redness after cataract surgery.

It is usually possible to successfully treat complications that arise from cataract surgery with medication or further surgery. Rarely, your vision may be worse than it was before surgery and there is also a very small risk (around one in 1,000) of permanent damage to your eye, causing a loss of sight.

However, the vast majority of people have a good result from surgery and are happy with the improvement in their vision.