Is it worth paying for deluxe lenses you can’t get on the NHS? DOS AND DON’TS AFTER A CATARACT OP

THERE are different types of artificial lenses used in cataract surgery. Most of these intraocular lenses, as they’re known, are made of acrylic that generally never wears out or breaks down. Here, we look at the choices — and their pros and cons . . .

WHAT YOU CAN GET ON THE NHS

MONOFOCAL IMPLANTS: These are singlefocus replacement lenses, which mean your eye is set at a fixed focus when they are inserted.

The problem with fixedfocus lenses, though, is that you may need to wear glasses, typically for reading or computer work. However, monofocal lenses do allow you to see things better in dim light, compared with multifocal lenses (see below).

Monofocal lenses have been the standard since intraocular lenses became a routine part of cataract surgery in the early Eighties. They are generally the cheapest (about £50 per lens) and are still used in the vast majority of NHS cataract operations.

Most people will have a lens focused on distance — although they can be set at reading or middle distance — according to Professor Stephen Vernon, a consultant eye surgeon in Nottingham and vice president of The Royal College of Ophthalmologists.

‘If your implant lens is set for distance, you will still need to wear glasses for reading or computer work,’ he explains.

A study of more than 55,000 NHS cataract operations, published in the journal Eye in 2012, found that more than 90 per cent of patients who had cataract surgery using a monofocal lens had good and clear vision afterwards.

Some surgeons offer micromonovision (also known as minimonovision), which uses the same monofocal lenses. However, one eye is set to focus at distance and the other focuses closer — normally at arm’s length from the eyes. This allows the eyes to work together to provide allround vision and, in some cases, does away with the need for glasses. (This technique is not widely available on the NHS.)

‘I have found micromonovision is suitable for many of my patients who want to be less reliant on spectacles in everyday life,’ says Professor Vernon. TORIC IMPLANTS: If you have astigmatism (where the front of the eye is shaped more like a rugby ball than a football, so that light focuses in more than one place at the back of the eye, causing blurry vision), your doctor may recommend toric implants.

You will still need glasses for near vision, as these are still monofocal lenses, but they improve distance vision for people with astigmatism.

‘These lenses are relatively new — they have been around for the past six to seven years — and work by focusing more of the light on the back of the eye, thereby reducing or neutralising the problem of astigmatism,’ says Professor Vernon, who also practises at BMI The Park Hospital in Nottingham.

Toric implants are suggested once you have an astigmatic prescription of two dioptres (a measure of your vision, with zero being normal).

Although available on the NHS in some hospitals, they are about £100 more expensive than standard monofocal lenses. As a result, some centres restrict their use to the worst cases. Also, the surgery required is more complex because toric lenses need to be inserted at a particular angle.

This means that the eye has to be marked before the operation, to make sure the lens is put in exactly the right place.

WHAT YOU’LL NEED TO GO PRIVATE FOR

AS WELL as monofocal implants and monovision (see above), the options that you can get privately include . . . MULTIFOCAL IMPLANTS: The aim of a multifocal lens is to enable patients to see at both near and distance at all times without the need for glasses. Patients using these implants have to learn to ‘ignore’ the image they are not concentrating on. (There are also multifocal toric lenses for people with astigmatism.)

Multifocals have been around for more than 20 years, but are not generally available on the NHS, as they are not considered costeffective.

Up to 12 per cent of patients will need to have them removed and replaced with a singlefocus lens.

‘While these sound wonderful and are exactly what people want, because they don’t wish to wear glasses after surgery, they can cause vision difficulties, particularly when driving at night, as oncoming headlights can cause considerable glare,’ says Professor Vernon.

‘This is down to the way the lens is made, with a series of concentric ridges built into the front surface of the lens, which disperse some of the light, in turn causing glare.’

He adds: ‘People particularly at risk of problems are those with high visual demands or perfectionists and those who have to drive at night.

‘A lot of patients have heard of these implants and ask if they would be suitable for them.

‘It’s very important that surgeons explain the risks and benefits carefully before patients go ahead with surgery — otherwise, they may simply end up swapping one problem for another.’ ACCOMMODATING IMPLANTS: These lenses attempt to allow near and distant vision without the need for glasses, by using a hinge to alter their focus as the patient looks from far to near.

The hinge allows the lens to move forward slightly when the eyes try to focus on a near object — they are effectively singlefocus lenses that move within the eye.

However, results of controlled trials have been mixed and the majority of studies show that these lenses currently don’t live up to expectations, with little or no change of focus occurring when the lenses have been in place for a few months.

‘These are not used on the NHS and are also not widely available privately because they currently don’t work very well for most patients,’ explains Professor Vernon.

‘While new generations of accommodating implants are in development, and early results are promising, it may be some time before we have enough research data to advise their use.’