Cataract

Cataract

Many people think poor vision is an unavoidable frustration of growing older.

It’s certainly true that cataracts often develop with age: as we get older, the lens of our eye become more susceptible to degeneration of proteins of the lens that cause frosting or cloudiness. But that doesn’t mean you have to endure them forever. Cataract surgery is a very common and highly effective procedure. It works by replacing the natural lens of the eye with a new, artificial lens. It’s swift (typically around 15-20 minutes per eye) and painless. And it can correct prescription issues at the same time, leaving you free to enjoy clear vision again – perhaps for the first time in years.

A cataract is a clouding or opacity of the eye’s natural lens. As we get older our lens loses elasticity, causing a deterioration in reading vision – a change known as presbyopia. A particular form of cataract known as nuclear sclerosis can cause a change in prescription which actually improves reading vision without glasses (myopic shift). Over time, gradual opacification of the lens occurs, and this obscures and clouds the vision. Any opacity of the lens we call cataracts.

How does the eye work? Read more about the structures of the eye in our learning section.

Cataracts are generally associated with the normal ageing process. Surprisingly, they can actually cause a temporary improvement in your near vision – but the effect is short-lived and disappears as the cataract worsens.

Cataracts can also develop prematurely in certain situations. For example:

  • following a direct injury to the eye
  • with medical conditions like diabetes
  • in patients who are undergoing steroid therapy
  • after previous eye surgery, or inflammation
  • at birth (congenital cataracts)

Many people think poor vision is inevitable as they get older, but for the vast majority of patients with lens opacity, cataract surgery is an extremely successful means of restoring vision.

Cataracts can manifest themselves in a number of ways. These include:

  • blurred vision, especially when looking at distant objects
  • glare from bright lights, especially car headlights at night
  • spectacle vision that seems dirty or scratched
  • frequently changing spectacle prescription
  • colours appearing washed out or faded
  • double vision in the affected eye

There are different types of cataract, and the visual aberrations you experience will depend on the type you have.

Cataracts usually develop slowly. In fact they generally have little impact on your vision at first: your local optometrist may be able to improve your vision with a change in spectacle prescription during the early stages. As the lens becomes cloudier, however, it begins to interfere with the light rays passing through to the retina. This will increasingly blur your eyesight. You will reach a stage where prescription changes no longer improve your vision.

Comparison of a healthy eye with a clear lens and an eye with lens opacity

Choosing when to have cataract surgery is usually a matter of personal choice, and we can talk you through the options when you come in to the clinic. But if your impaired vision is beginning to interfere with daily life, it’s definitely worth considering.

You may notice problems with your vision when working, watching TV, driving, playing sport or caring for others. If you are a driver, you must be able to achieve the visual standard required by the DVLA and it may be necessary to have cataract surgery in order to keep your licence.

Leaving a cataract untreated doesn’t damage the eye. But as the lens opacity worsens, your eyesight will deteriorate until little vision remains. Surgery at this stage may be more difficult. Complications can arise if the thickened lens causes the pressure in your eyes to increase, although this is unusual and we will tell you if you’re at risk of it happening.

No. In the past, eye specialists would delay surgery until a cataract was ‘ripe’ or ‘mature’ – meaning that the patient was severely visually compromised and the lens had reached a stage favouring the old method of extraction.

Thanks to major developments in the surgical technique itself, the very low risk of complications and the visual benefits of modern, intraocular lenses (IOLs), we can now perform cataract surgery much earlier.

As with spectacles, there are different kinds of implant lenses. You may be able to choose between a regular monofocal lens (that is, a lens with single-vision power) or a multifocal lens that’s designed to give you a degree of freedom from glasses for most everyday tasks.

We can talk through these options when you come into clinic – both the type of implant lens that will best suit you, and the visual outcome you can expect. It’s important to note that the advanced multifocal lenses are not suitable for everyone, and some patients may still require a spectacle prescription following surgery.

All our patients have a biometry measurement before cataract surgery. This allows us to calculate the correct power for your implant lens. It doesn’t involve touching the eye. You simply sit and look into a machine while it takes your measurements.

We can assess the medical health of most patients on the day of surgery, but occasionally you may require a pre-assessment. Again, we can discuss this at your initial consultation.

If you use contact lenses already, you must refrain from wearing them for two weeks before biometry is carried out, and for 24 hours prior to your surgery. However, if you wear rigid gas permeable lenses, a longer period of spectacle wear prior to biometry will be required.

Since most cataract surgery is only carried out with drops to numb the eye (known as ‘topical anaesthesia’), there are usually no restrictions on what you can eat and drink prior to admission. If you require a general anaesthetic, we can supply you with additional written information to advise you about this.

The procedure is usually carried out as a day case, with a hospital stay of a few hours. Please remember that you won’t be able to drive yourself to hospital. You may like to ask a relative or friend to accompany you, or to drop you off and collect you when you’re ready to go home. If getting to and from the hospital is difficult, we may be able to offer assistance; please alert the secretarial team, since the hospital bookings office won’t be able to help with transport.

What will my surgery journey look like? Find out more about preparing for surgery with our handy infographic.

Most cataract surgery today is carried out using topical anaesthesia. This is done with eye drops to numb the eye and surrounding area. You will be awake during the operation and aware of some movement, touch and water, but the procedure will be painless. We routinely offer intravenous sedation, which many people find reassuring and relaxing.

For potentially challenging cases, we may recommend a local anaesthetic block for your treatment. This involves gently injecting anaesthetic around the eye, and it will help you to relax while the procedure is carried out.

We will make sure you feel comfortable on the operating couch. We then thoroughly cleanse the skin around your eye and place a sterile cover (or ‘drape’) over your eye and face. The cover will be lifted off your mouth so you can breathe and talk easily. A tiny clip is used to hold your eyelids gently open. The surgeon will then ask you to look at a central light, which allows us to position your eye correctly for surgery.

Since you will only see a little of what’s happening during surgery, we will explain what we are doing as the operation goes along. The theatre staff will be on hand to help you feel relaxed and comfortable. We can even make sure that someone is there to hold your hand if you wish. The operation usually takes about 15 to 20 minutes, though in some cases it may take longer.

Many people believe that cataracts are removed with lasers, but that’s not usually the case. The modern technique for extracting cataracts is called phacoemulsification. It’s carried out under an operating microscope and involves making a very small incision in the cornea (the clear part at the front of the eye, which covers the iris and pupil). We then insert a tiny probe through the incision to remove the cloudy lens. The incision is self-sealing, so stitches are not required.

The natural lens of the eye is contained within a ‘capsular bag’. The aim of surgery is to remove the lens contents while leaving the capsular bag intact, apart from a small circular hole on the front surface which allows us to perform the operation.

An ultrasonic probe breaks up and then vacuums away the cataract material, leaving a cavity for the new lens.
We then gently slip the rolled-up implant lens into the eye through the tiny corneal incision. Once situated within the capsular bag, it unrolls and we adjust it into position. You will not be able to feel this new lens.
An easy way to visualise the process is to think of the cataract as a smartie. Removing the chocolate would leave an empty case. This is where the new implant lens will sit.

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