Planning your operation

Which implant lens should you have?
What do you need to consider prior to surgery?


Which implant lens should you have?

A growing number of quality intra-ocular lenses are now available to help those individuals wishing to minimise their dependence upon spectacle wear.

Different styles of implant lens suit different patients according to their particular visual needs, hobbies or sporting interests. There are advantages and disadvantages to be considered with each style of lens and it is important that before choosing an implant you are fully aware of its benefits and limitations.


Types of multifocal implant lens

Broadly speaking multifocal lenses can be divided into those having intrinsically more than one focal power, likened to a varifocal spectacle lens and those which have a single power but change their focal effect by a degree of movement, known as “accommodation” within the eye.


Multifocal lenses

There are two main forms of multifocal lens and these take their names from the way in which light rays are converged.

Refractive implants have more than one curvature producing a variety of focal points to give clear vision at distances between reading and infinity.

Diffractive lenses work on a different principle, using an edge-effect to bend light, the implant appearing as having a series of concentric circles either across all of the lens or confined to a central portion.

Choosing the right multifocal lens depends upon many factors including the refractive error of the eye (are you long-sighted, short-sighted or astigmatic?), specific visual needs and an acceptance of the limitations inherent in any of the available implant systems.

We will help you decide if a multifocal lens is right for you and which of the many available options will best suit your needs.


Examples of multifocal lenses

The ReZOOM lens; this is a refractive lens designed to help patients see over a range of focal lengths. Good vision may be possible for near, intermediate and distance ranges.

Some images can appear blurred and bright lights may be difficult to tolerate. Reading is not always easy.

The ReSTOR lens; this is a popular implant with a diffractive portion giving good near vision. This is favoured by patients who require reading vision and distance vision with a lesser concern for intermediate distance such as for computer work. Long-sighted patients are particularly impressed by the ReSTOR lens.

Halos can appear around points of light which can be troublesome when driving at night. Bright fluorescent lighting, as used in supermarkets, can appear dazzling.

The AcriLISA lens; this is another diffractive style of lens but giving more priority to distance rather than near vision.

Halos and glare are perceived by some patients.

Accommodating lenses

The Tetraflex lens; this is an accommodating lens which has a single refractive power, but changes its effect by backward and forward movement within the eye.

The natural and subconscious effort that we make when reading changes the shape of the human lens. With the new Tetraflex lens in place, this change pushes forwards the optical part of the implant, which is “hinged”. As the lens moves forwards, its effective power changes, assuming a focus for near vision rather than distance.

This lens is not associated with many of the troublesome optical phenomena of the diffractive lenses and would be more suitable, for example, in those who need good night-time driving vision.

The Tetraflex lens will have a lesser effect in short-sighted eyes and in any eye the degree of reading vision is unpredictable.


Monovision refers to the situation in which one eye is focused for distance and the fellow eye focused for near. This technique is sometimes used for contact lens wearers who are developing presbyopia.

Only a small degree of difference between the two eyes is tolerated comfortably and it is important that if one eye is dominant, it is set to be focused for distance vision. The fellow eye is focused at arms length to help with tasks such as seeing the price on a supermarket shelf, reading text on a mobile phone, looking at a car dashboard, reading larger news print, cooking and eating.

Monovision does not usually give patients the ability to read fine print, for example the telephone directory and for these detailed close tasks reading spectacles will still be required.

For all patients undergoing refractive lens exchange surgery, biometry measurements will be taken to ensure that an implant lens of the correct power is selected. This involves sitting at a machine that, without touching the eye, takes various measurements. We can then calculate the most appropriate lens power for you.

Most patients can be assessed on the day of surgery, but occasionally a pre-assessment is required. This will be discussed at your initial consultation.

If you use contact lenses you must refrain from wearing them for two weeks before biometry is carried out, and for forty-eight hours prior to your surgery.

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What do you need to consider prior to surgery?

It is important that we have knowledge of any prescribed medications you are taking. You will probably be asked to continue these in the usual way, but some medications can cause complications during any surgical procedure.

As most refractive lens exchange surgery is carried out using just drops to numb the eye (referred to as “topical anaesthesia”) there are usually no restrictions on what you may eat and drink prior to admission. Written information will give additional advice should, for example, sedation be required.

Once a decision has been made to proceed with surgery, our secretarial team will liaise with you to arrange a convenient date on one of our operating lists. This will be at one of the ophthalmic units in the Southampton or Guildford areas.

You will receive confirmation of your admission date and time from the hospital bookings department, together with a health questionnaire and some general information about your chosen hospital. The procedure is usually carried out as a day case, with a hospital stay of several hours.

Remember, you should not drive yourself to the hospital. You may want a relative or friend to accompany you, or to drop you off and return to collect you when you are ready to go home. Alternatively if you find getting to and from the hospital difficult, we may be able to offer assistance. Please alert the secretarial team if this is the case as the hospital bookings office are not able to help with transport arrangements.

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