Artificial lens implant
Lens implant surgery (also called refractive lens surgery or refractive lens exchange) is a surgical procedure to remove the natural lens of the eye and replace it with an artificial lens, or intra-ocular lens implant (IOL).
The lens implants are specially engineered to provide focussing power to suit the individual, and the procedure is done to reduce reliance on glasses. It’s identical to a cataract operation, but a cataract operation is normally done to remove the natural lens because it has become cloudy and is interfering with vision.
Refractive error and the need for glasses
The cornea, the clear window at the front of the eye, and the lens focus light onto the retina, the light-sensitive layer at the back of the eye. The cornea provides about 75% of the refracting (focusing) power of the eye. The lens inside the eye provides the remaining power. The shape or curvature of the cornea determines how well you see and how in focus an image is when it reaches the brain.
The retina sends the ‘picture’ of the viewed object to the brain where the object is then ‘seen’. Normally, the eye is able to focus an image of an object at any distance without the need for corrective lenses. An inability to do this is a refractive error and until fairly recently could only be corrected by glasses or contact lenses. Refractive errors are caused by an imbalance between the refractive power of the eye and the length of the eyeball. This means that light rays from an object are not focused clearly on the retina, leading to blurred or misty vision.
The picture here is of an eye with normal vision. Light from a distant object (the red lines) is focused correctly by the cornea and lens onto the retina, so a clear image is seen.
Refractive error - the need for glasses
Myopia (near-sightedness, short-sightedness) is an inability to see objects in the distance clearly without glasses, although it may be possible to see close-up or read, without correction. Light from a distant object is focused in front of the retina.
Hyperopia (long-sightedness, far-sightedness) is an inability to see near objects without glasses. Objects in the distance are also blurred, but less so. Light from a distant object is focused behind the retina.
Astigmatism is a condition where the cornea is more curved in one direction than another, rather like a rugby ball compared to a football. This leads to unequal focusing of light from an object, leading to two focal points and blurry vision.
How is lens implant surgery done?
The procedure is identical to a cataract operation. A local anaesthetic is administered, and then sterile drapes are applied to the skin around the eye. A tiny incision is made in the cornea, the clear part of the front of the eye, and an ultrasonic probe is used to soften the natural lens and remove it. The incision is so small it doesn’t need any stitches. The technique is known as Phakoemulsification or ‘Phako’ for short (From the Greek: phakos = lens, and Latin:emulsification = to turn into milk!).
An intra-ocular lens implant (or IOL) is then inserted, folded, into the space left where the natural lens used to be. The lens gently unfolds into exactly its original shape.
The lens membrane, or capsular bag, is left intact to provide support for the new lens. There are modern lasers that will do parts of the surgery, but there has yet to be convincing evidence that they are superior to current techniques.
1) A tiny incision is made in the edge of the cornea, the clear part of the front of the eye, allowing access to the front chamber of the eye.
2) A circular opening is made in the transparent lens capsule.
3) An ultrasonic instrument is used to remove the lens leaving the clear lens membrane ‘bag’ behind.
4) The intra-ocular lens implant is injected, and folded, into the capsular bag where it unfolds into place. No stitches are required.
It's a familiar technique which is frequently performed.
The techniques involved are identical to cataract surgery which is a very frequently performed operation. The technology behind the surgery has evolved to a very sophisticated level over the years. Modern lens measurement techniques result in a high degree of accuracy when calculating the power of the lens implant required.
The visual outcome is generally quite stable.
The natural lens in the eye changes throughout life, and it is this change that is largely
responsible for keeping Opticians in business! If your natural lens is replaced, then you should not experience any significant shift in your spectacle requirement (or lack thereof) over the years. It is also, of course, impossible to develop cataracts in the future if you have had lens implant surgery.
Lens implant technology has improved.
Lens implants continue to evolve, although the basic design hasn’t altered much over the years. There are now lenses to suit even those with very high prescriptions and for those with significant astigmatism. Multifocal lenses have improved considerably since they were first used about 20 years ago.
People with very high prescriptions can be treated.
Laser surgery can only treat a certain amount of error, but lens implant surgery can cope with
almost all types and degrees of spectacle error. Bespoke lenses can be specially manufactured to treat those with very complex prescriptions. Lens surgery may be suitable for others for whom laser isn’t an option, such as those with dry eyes or corneal scarring.
In general, 95% of patients will have no problems at all either during or after surgery. Of the remaining 5%, most will only have minor problems that can either be dealt with at the time or will get better by themselves and do not affect the outcome of the surgery. Some however will need further treatment, including further surgery. 0.1% of patients (1 in every 1000) may have a problem that results in loss of vision.
The consultation is an excellent opportunity to discuss any aspect of the surgery.
At the consultation, your consultant will advise you on your suitability for lens surgery, and what can be achieved, and what can’t. Making sure that expectations are realistic is fundamental to success. The aim always is to get as good an outcome as possible, but it’s important to bear in mind that there is a degree of variation between individuals and that there is a small risk of complications, and as a result, not everyone will be 100% satisfied afterwards.
Most patients find that after surgery their unaided vision is significantly improved, although there may still be a small spectacle error present. If you wouldn’t be prepared to accept anything that’s less than perfect, then you would need to consider very carefully whether lens implant surgery is right for you or not.
There are 3 main types of lens implant:
An intra-ocular lens implant, or IOL, is an artificial lens that is precisely manufactured and engineered to go inside the eye. They come in a range of styles and strengths, and a key part of the consultation is deciding which type of lens would be the best to suit the requirements of the individual.
Lens technology has improved significantly since they were first conceived in the late 50’s. There are now lenses that can correct very high spectacle error, including astigmatism, and also correct vision for distance and near using multifocal optics.
The consultant ophthalmologists use Aspheric lenses, which are designed to give the best quality vision. These would be suitable for patients who don’t mind wearing reading glasses, although often it is possible to offset the focus in one eye to allow ‘blended’ vision (often called monovision). This can work well, especially if this has already been experienced with contact lenses.
These lenses are specially designed to provide multiple focal points for both distance and near vision, and some of the very latest lenses can provide intermediate vision as well. They are excellent for those who are very motivated to reduce reliance on reading glasses. They are generally very successful, but there is a degree of compromise. Some will notice glare and halos around lights, especially at night, and a small percentage will find these troublesome. These effects often improve with time.
Both monofocal and multifocal lenses are available in a toric form. Toric lenses are designed to help astigmatism – the condition where your eye is shaped more like a rugby ball than a football. A small degree of astigmatism is extremely common and almost normal; higher degrees of astigmatism are treatable with toric implants but there may be a small amount of remaining spectacle error that requires correction with glasses.
You may be suitable if you are:
Realistic and well-informed about what can and can’t be achieved with lens implants.
Short-sighted with a high spectacle prescription.
Long-sighted, needing glasses for distance as well as for near.
Getting early lens changes or cataract formation.
Those generally unsuitable (with some exceptions) are:
Younger patients (in general under the age of 50, although in some cases patients in their 40’s could be candidates)
Those with only slight degrees of spectacle error.
You may be covered by private medical insurance, or you may wish to consider spreading the cost of your surgery by opting for a monthly payment plan.
We aim to make our costs as transparent as possible, but it’s important to talk everything through in detail with your consultant at the time of your appointment. Some costs may be paid directly to the hospital, while others, such as your consultant fees, may be paid directly to the consultant.
Does the lens implant wear out?
No – the lens is made from a high-tech acrylic polymer that is completely inert. There are no moving parts, so the lens can’t wear out. They are designed to last a lifetime.
Do you treat both eyes at the same time?
There are some surgeons who treat both eyes at the same time, and it is probably safe to do so. However, common practice is to treat one eye at a time. The main advantage is to see what the outcome is like for the first eye – this sometimes allows slight modifications to the lens power for the second eye to better suit individual requirements.
Can I have a general anaesthetic?
95% of patients are fine under just a local anaesthetic. However, if anxiety is a major issue for you, then a general anaesthetic may be preferable.
Can the lens grow back?
No, but some (roughly 10%) may notice blurring of vision some years after having successful surgery. This is due to clouding of the transparent membrane that is left behind to support the artificial lens. If vision is affected then it can be treated with a special laser, the YAG laser, which allows the surgeon to make a hole in the cloudy capsule and clear the vision.
Will I see anything during the surgery?
Right at the start you may see something, but very quickly this gets very blurry. Vague shapes and movements may be seen, and some notice vivid coloured lights.
What if I cough/move/blink during the operation?
A gentle metal spring device is used to hold the eyelids apart, so you don’t have to worry about blinking. A nurse or orderly will hold your hand during the procedure if you wish, and you
can indicate if you feel the need to cough or sneeze, and the procedure can be paused.
What do I do between my procedures as far as glasses are concerned?
Your consultant will provide specific advice tailored to the individual. This may be to wear just one contact lens or go without glasses.
How soon can I exercise after surgery?
Gentle low-impact exercise can be resumed after a few days. High-impact activities such as running ought to be avoided for at least a fortnight. You should also avoid swimming for a fortnight.
Will I need glasses afterwards?
Reading glasses are commonly required unless you have had ‘blended vision’ or a multifocal lens. Your consultant will discuss with you your likely post-operative spectacle requirement at the consultation. ‘Off the shelf’ ready readers can be a useful temporary solution.
Do I need to see my optician again?
Your consultant will advise on the need for glasses afterwards, and your outside optician will then do an eye test and dispense glasses in the normal way. Even if no glasses are required, then a regular routine check-up on eye health is a good idea every 18 months or so.
When can I start to use eye make-up?
Avoid eye make-up and mascara for at least two weeks. Facial products such as foundation and powders may be used carefully after a day or so.
Will my vision change as I get older?
Changes in the natural lens are usually the reason why vision alters as one gets older. After a lens implant operation, the vision should be much more stable. Small changes in the
requirement for glasses are however possible in the future. It is of course, impossible to develop cataracts once you have had lens implant surgery.
Combining a calming hospital environment with outstanding patient care so you can recover as quickly as possible.
Type of anaesthetic Local
Covered by health insurance? Yes
Can I pay privately? Yes
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