Risks and Benefits of Cataract Surgery

Patient Experience

  • Reference Number: HEY-012/2023
  • Departments: Ophthalmology Department
  • Last Updated: 1 September 2023


This leaflet has been produced to give you general information.  Most of your questions should be answered by this leaflet.  It is not intended to replace the discussion between you and the healthcare team but may act as a starting point for discussion. If after reading it you have any concerns or require further explanation, please discuss this with a member of the healthcare team.

What is a cataract?

A cataract occurs when the lens inside the eye has become cloudy. This happens naturally as you get older. Sometimes a cataract develops in younger people due to other medical conditions, such as diabetes, following inflammatory conditions such as uveitis, or an injury to the lens of the eye.

Why do I need cataract surgery?

The cataract surgery is mostly carried out to improve clarity of vision.

Due to the development of modern surgical techniques, it is not necessary to wait for the cataract to “become ripe”. The cataract operation can be done at any time but obviously it must be worth the small percentage risk. In other words, the procedure will be carried out if it is affecting your lifestyle. This depends on how you feel your vision is affected and following advice from your consultant about the risks of the procedure.

You will also be advised about the presence of other conditions of the eye that may limit the success of the operation, or which might make the operation a little more risky. You are likely to be less dependent on spectacles for distance vision and may only need reading glasses.

How is the operation undertaken?

The cataract is removed through a vibrating needle (using ultrasound energy), by a flow of fluid; a procedure called phacoemulsification.  This is the safest operation at present because the small wound seals rapidly and, hardly ever requires stitches. The machine we use to remove the cataract is “state of the art”. We may also use a laser (femtosecond laser) to carry out a part of the cataract surgery in some cases.

To get to the cataract a small wound is made at the edge of the cornea, the clear window of the eye. Once the cataract is removed, a clear artificial lens (intraocular lens implant or IOL), made of plastic-like material (acrylic), is placed inside the eye.

Do I need to wear glasses after cataract surgery?

Most people will still need glasses after cataract surgery.

The artificial intraocular lens implants (IOL) come in different strengths (powers) and the surgeon can choose an IOL that gives you better focus for either distance or close vision.

In most of the cases, the IOL which gives good distance vision will be implanted so that you are less dependent on spectacles for distance vision. You will need glasses for reading mainly, although you may still need glasses for fine focusing for distance.

Some people may prefer to have good close vision without glasses (for reading or for detailed close work such as embroidery). If you choose this option, you will need glasses for distance mainly. This option can be discussed with your surgeon at your cataract assessment clinic visit.

Multifocal IOLs are lenses that aim to correct vision for both distance and near, so that you are largely spectacle independent; but they are not available on the NHS.

Can there be any complications or risks?

As with all surgeries, there are small risks involved. The complications of cataract operations are rare but can be very serious, with potential life changing effects, so we are obliged to discuss these with you.  Most complications of surgery can be managed successfully.  All of these complications can lead to a delay in recovery of your eye. You may require further operations or treatment and require further follow up appointments. In rare circumstances, you may need to stay in hospital for treatment of complications.

Generally speaking, the risk of losing the sight or even the eye from cataract surgery has been put at less than 0.03%.

You can be rest assured that we do not consider surgery for your eye without weighing up the risks and advantages of surgery with you.  We will discuss any additional risks that apply to your situation at the pre-operative assessment clinic.  Bearing these risks in mind, cataract surgery should not be undertaken lightly. It is not a “simple operation.” It is a major operation on your eye.

The risks and complications associated with cataract surgery are detailed below.  The list is not exhaustive, as rare or very unusual complications can occur. The final result from surgery cannot be guaranteed.

During surgery

  • During the operation we normally place the implant (intraocular lens) on the membrane, which was part of the cataract (called the posterior capsule). For various reasons, a hole may develop in this membrane (posterior capsule rupture) and this may lead to further complications. It may be necessary to place the implant in a different position within the eye, or it may be necessary to delay inserting the lens implant until a later date.
  • If there is a hole in the capsule, then vitreous humor (the gel within the back of the eye) may escape, increasing the risk of retinal detachment and requiring further surgical manoeuvres, either during the cataract operation or at a later date.
  • Another complication of posterior capsule rupture is that a part of, or all of the cataract, may drop into the back half of the eye. This complication requires further specialist surgery. This may be done the same day or within a few days.
  • Bleeding can occur within the eye during surgery and this can lead to loss of sight.
  • Local anaesthetic procedures can also cause bruising behind the eye. This can delay the surgery, or lead to loss of vision due to pressure on the eye nerve.
  • Most cataract operations are carried out using a small incision technique but some have to be “converted” to a larger wound technique due to technical difficulties during surgery. In some cases, your surgeon will decide from the outset that the larger wound technique is appropriate for your eye condition. Studies have shown that visual results at one year after the operation are very similar between the techniques. Larger wounds require stitches, which may have to be removed or adjusted in the post-operative period.
  • Although small incisions are not routinely stitched, it may be necessary to apply one or two stitches to a small wound if necessary during the surgery. These stitches can usually be removed soon after the operation (a painless out-patient procedure).

Following surgery

  • The cornea (clear window at the front of the eye) may react badly to cataract surgery and become very swollen and hazy. This can cause permanent reduction in vision. In many patients this can be treated with additional eye drops on a long term basis, or may rarely need an operation called a corneal graft at a later date.
  • The normal process of the vitreous attachments to the retina becoming weakened as you age may be hastened by surgery on the eye. This process is called ‘posterior vitreous detachment’ and is normally characterised by flashes of light and floaters. In a small number of people this process may cause holes to form in the retina causing a retinal
    detachment. If this occurs, an additional operation may be required to repair this. This may happen several months after eye surgery.
  • Endophthalmitis – It is possible to develop this serious infection inside the eye. The treatment for this type of infection involves further operation(s) to take samples and to allow injection of antibiotics into the eye. Treatment has to be very prompt if it is to be effective. 50% of cases of endophthalmitis do not recover sight despite treatment. Very rarely does an eye have to be removed because of infection.
  • In extremely rare cases during the local anaesthetic injection, it is possible for the eye to be punctured by the needle. This can lead to retinal detachment, bleeding or loss of vision.
  • We may also discover more than the usual amount of inflammation within the eye following the operation. This is uncommon but will require an increase in strength or frequency of drops, or we may have to use medicines by injection, or taken orally to combat this.
  • Sometimes there is a higher than normal eye pressure following cataract surgery. This may require the use of extra eye drops, pills or injections.
  • Some patients may get bruising around the eyelids in the days following surgery.  This type of bruising resolves over a few days.
  • Cystoid Macular oedema – This is swelling (waterlogging) in the central part of the retina and can occur in 1- 5% of patients following cataract surgery. This leads to blurred vision. It can develop within the first few weeks of the operation. This is treated with additional anti- inflammatory eye drops for a period of weeks, or sometimes a steroid injection into the eye or next to the eye and in most patients, settles down with no lasting effect.
  • Sometimes a patient may not get the expected post-operative vision and could be left with short sightedness or long sightedness or astigmatism requiring spectacles, contact lenses or, rarely, corrective surgery or laser.
  • Rarely, the lens implant may dislocate into a wrong position, with time.
  • In some cases, the upper eyelid may become droopy.
  • Some patients may notice glare, halos, reflections or a feeling of blurred vision or discomfort following uncomplicated surgery and the eye will be apparently healthy on examination. These cannot be prevented or treated.  They usually become less obvious with time.
  • Cataract surgery may worsen pre-existing eye conditions, such as glaucoma, uveitis (inflammatory eye disease) or corneal diseases.
  • There is a tendency for the clear membranes behind the artificial lens implant to become cloudy over a period of time. The risk of this happening is about 50% in five years when a perspex implant is used. However, the implants that we use are acrylic which carry a lower risk of opacification (cloudiness) – between 5 and 30% within five years. If membrane opacification does develop, an outpatient laser procedure can be carried out very easily to restore the vision.

How do I prepare for the operation?

Please read the information leaflet.  Share the information it contains with your partner and family (if you wish), so that they can be of help and support.  There may be information they need to know, especially if they are taking care of you following this operation.

You will attend a ‘preoperative cataract assessment clinic’. If cataract surgery is indicated and you wish to go ahead with surgery, then you will be given additional information leaflets detailing what happens when you come in for surgery, how to use eye drops and the do’s and don’ts following surgery.

In most patients, cataract surgery is carried out under a local anaesthetic as a day case operation. The type of anaesthetic you may be suitable for will be discussed with you by the eye surgeon at the pre-assessment visit.

Please be aware that the Eye Department is a teaching unit and that many operations in whole or part can be carried out by trainee eye doctors under supervision. We cannot give a guarantee that a particular surgeon will perform the procedure. The surgeon will however, have appropriate experience or will be supervised.

What happens afterwards?

If the decision to go ahead with surgery is made, you will be offered a date to come in for your surgery. This will be confirmed in writing. In some circumstances, the original date may have to be altered, in which case you will be notified by a letter or phone call.

Should you require further advice on the issues contained in this leaflet, please do not hesitate to contact the Ophthalmology Department 

Eye Clinic (01482) 608788 – (Monday-Friday 8.30am-5.00pm) 

Ward 35, Hull Royal Infirmary on (01482) 604346

General Advice and Consent

Most of your questions should have been answered by this leaflet, but remember that this is only a starting point for discussion with the healthcare team.

Consent to treatment

Before any doctor, nurse or therapist examines or treats you, they must seek your consent or permission. In order to make a decision, you need to have information from health professionals about the treatment or investigation which is being offered to you. You should always ask them more questions if you do not understand or if you want more information.

The information you receive should be about your condition, the alternatives available to you, and whether it carries risks as well as the benefits. What is important is that your consent is genuine or valid. That means:

  • you must be able to give your consent
  • you must be given enough information to enable you to make a decision
  • you must be acting under your own free will and not under the strong influence of another person

Information about you

We collect and use your information to provide you with care and treatment. As part of your care, information about you will be shared between members of a healthcare team, some of whom you may not meet. Your information may also be used to help train staff, to check the quality of our care, to manage and plan the health service, and to help with research. Wherever possible we use anonymous data.

We may pass on relevant information to other health organisations that provide you with care. All information is treated as strictly confidential and is not given to anyone who does not need it. If you have any concerns please ask your doctor, or the person caring for you.

Under the General Data Protection Regulation and the Data Protection Act 2018 we are responsible for maintaining the confidentiality of any information we hold about you. For further information visit the following page: Confidential Information about You.

If you or your carer needs information about your health and wellbeing and about your care and treatment in a different format, such as large print, braille or audio, due to disability, impairment or sensory loss, please advise a member of staff and this can be arranged.

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