Multi-Focal Intra-Ocular Lens


Multi-focal intra-ocular lenses have special features that give you good near, intermediate and distance vision-all in one lens.

Multifocal intraocular lenses give you a good chance of living glasses-free for the majority of your activities after cataract surgery. A multifocal IOL  can have many designs varying from bifocal lens to one that resembles a bulls-eye target, with concentric circles for near, intermediate and distance vision. Your brain automatically zeros in on the range of vision you need-so you can see objects well at all distances.

Multifocal intraocular lenses are an excellent choice if you:

  • Want to reduce your dependence on glasses or contacts as much as possible.
  • Do not have astigmatism or are willing to address your astigmatism by wearing corrective lenses or by having additional surgeries such as LASIK or limbal relaxing incisions.
  • Are less comfortable adapting to change and learning new skills.
  • Are willing to risk some minor night vision symptoms.

If you wish to reduce your dependence on glasses or contacts but multifocal lenses don’t seem like a good match for your needs, consider accommodative intraocular lenses or monovision.

Who are Multifocal Intraocular Lenses for?

With standard monofocal lenses it is possible to achieve good visual acuity for distance after cataract surgery, but near vision becomes blurry.  For this reason, reading glasses are needed with this type of surgery, and many patients are not satisfied.

Multifocal lenses are designed for anyone who would like to enjoy good vision at all distances, ranging from distant to near.  With this solution patients can enjoy good vision without spectacles for all types of tasks, including driving, sports, watching television, using the computer, sewing and reading.  Selection of the type of multifocal lens depends on each patient and the opinion of the ophthalmologist, as there are different models and manufacturers which cater for different situations.

What types of Multifocal Intra-Ocular Lenses are available and how do they work?

REFRACTIVE INTRAOCULAR LENSES

Refractive intraocular lenses have an optic with different powers distributed in different areas.

Diseño de Lente Intraocular Multifocal

Multifocal IOL Design (allaboutvision.com)

An example of this type of lens is the AMO ReZoom.  They provide good distance vision but the visual performance from intermediate to near vision is variable.  The central area of the lens is designed for distance.  Then there is an area adapted for near vision and so on. Areas for near and distance are alternated. The pupil plays an important role in this design and can become a disadvantage.  If the pupil contracts significantly, the most effective area will be the centre, meaning that distance vision will remain good but near vision quality will be lost.

On the down side, there is a higher incidence of halo effect and glare than with other lens types, such as diffractive.  Even so, the success rate is high and the results are satisfactory.

TRIFOCAL MULTIFOCAL INTRAOCULAR LENSES

Trifocal lenses have concentric rings with different refractive powers which redirect the light to three different focuses: distance, intermediate and near vision.  The lens has a basic power calculated for distance and the corresponding rings are on its periphery.  Then, there are the rings for intermediate distance which are approximately 1.66D stronger to achieve focus.  Finally, the more central rings are those responsible for near vision and are around 3.33D stronger than the refraction for distance.

This optic designed not to depend on the pupil size, and works when the pupil is contracted (high illumination) and dilated (low illumination).

The most modern lenses are aspherical and are designed to minimize unwanted optical effects after surgery, such as halos or glare, especially to improve night vision.

It is a treatment option which produces very good visual quality at all distances, and as a result, independence from spectacles.  It can be implanted for both cataract surgery and for refractive lens surgery.

DIFFRACTIVE MULTIFOCAL INTRAOCULAR LENSES

Concepto de Lente Intraocular Multifocal

Multifocal IOL

In the case of diffractive lenses, there are various areas with different optical powers.  There is a series of concentric rings which form a “diffraction network”. This optical feature has the capacity to direct rays of light to two different focuses at the same time, thereby creating two separate focal points, one for distance and the other for near.

With diffractive lenses, the light reaches the entire surface of the lens and there is therefore no dependency on the pupil size.  They can cause glare at night when driving and produce a halo effect.

Lente Intraocular Multifocal - Haz de Luz

Multifocal IOL

The diagram on the right shows the different areas with different optical powers.  In the central area, the rays focus closer to the lens (higher power) and in the outer area they focus further away (lower power)

APODISED DIFFRACTIVE LENSES:

Apodised diffractive multifocal lenses have two areas.

lente-intraocular-multifocal-apodizada-1

The first is the central one, where the apodised area is located. This means that this area contains concentric levels of different heights, which decrease as they move from the centre to the periphery.  This makes the lens diffractive.  It is technology which allows for optimum light distribution to different focus distances, both distant and near.  It does not depend on lighting conditions.

The second area is the periphery of the lens, which surrounds the apodised region.  This part takes care of distance vision and directs the rays of light to a distant focal point.

This technology is patented by the intraocular lens AcrySofMR IQ ReSTORMR.

lente-intraocular-multifocal-apodizada-2

The aim is to reduce potential optical discomfort which may arise after cataract surgery as much as possible compared to other intraocular lenses, in addition to achieving good image quality.  Thanks to this, independence from spectacles can be easily achieved.

ASYMMETRIC MULTIFOCAL INTRAOCULAR LENSES:

Asymmetric Multifocal Intraocular Lens

Asymmetric Multifocal Intraocular Lens (Oculentis.com)

All multifocal lenses available on the market today have been created based on the concept of rotational symmetry: refractive, diffractive or apodised diffractive multifocal lenses.

This means that they are composed of circles or concentric areas which provide distance and near vision on an alternate basis.

There is now an innovative multifocal lens concept, which comprises an aspherical and asymmetric area for distance vision next to an area for near vision.  In other words, it is a lens with modifications in the radius of curvature to adapt to different distances.

The aim of this is to avoid “image jumps” which can happen with other designs.  This optical design functions independently from the pupil size, which is an advantage.

TORIC MULTIFOCAL INTRAOCULAR LENSES:

Toric Multifocal Intraocular Lens

Toric Multifocal Intraocular Lens (alcon.com)

Until recently, it was not possible to correct presbyopia and astigmatism simultaneously during a single operation.  There were no multifocal lenses which could cover all the requirements at the same time.  Today, patients with astigmatism are now able to enjoy independence from spectacles too. It is a very recent solution which confirms the major advances on today’s market.  These lenses have the ability to correct presbyopia and astigmatism at the same time.  As a result, patients can enjoy good vision at all distances. Today’s lenses are also made with an aspherical design to reduce spherical aberration as much as possible and improve visual acuity in nocturnal conditions.  These lenses are effective when corneal astigmatism is over one dioptre.

The multifocal optic of this lens can have different characteristics.  There are designs which are refractive, apodised diffractive and even with the same characteristics as an asymmetric lens.  A large visual field is obtained at all distances: distant, intermediate and near.

What are the pros and cons of multifocal lenses?

Today, innovative multifocal lenses are less invasive, and over time the brain adapts to diminish the optic phenomena caused.  For many patients, the new quality of life without spectacles is better and more important than the minor optical disadvantages which arise after surgery. Certain activities which have not required the use of spectacles for a long time such as reading, sewing or using a computer can continue to be performed after surgery with a multifocal intraocular lens.  People who are more demanding in this aspect are good candidates for multifocal lens implants.  In any case, it is important to be aware that the use of spectacles may be required for more infrequent, specific tasks.

In some cases, depending on the lens implanted and the post-surgical result, it is true that there may be minor side effects such as glare, halo effect or increase in aberrations.  Over time the neurological system will adapt to this new situation and the patient will become accustomed.  Adaptation varies according to person and can take a few months.  To ensure total adaptation, if possible both eyes must have been operated on under the same conditions and with the same lens.

Some form of correction may need to be performed after surgery which has produced a residual refraction. Your ophthalmologist will advise you on the need to perform a LASIK procedure, an implant of an additional intraocular lens (Add-On) or make limbal incisions to treat a minor astigmatism.

References

www.newlens.co.uk


More Information about Multi-Focal Intra-Ocular Lens

For more information regarding this treatment as well as any frequently asked questions, please see below.

Multifocal IOLs have a very high success rate and give you a good chance of not needing glasses after cataract surgery. A large majority of patients report enough eyesight improvement that they either never or only occasionally need to wear glasses after surgery. As with all surgery, patients with additional health conditions should ask their doctor what they can reasonably expect in their specific case.

It may take several weeks to several months for you to reach your best eyesight improvement. And it is usually recommended to have cataract surgery on both eyes within a few weeks time, so the brain does not need to adjust to unbalanced vision while only one eye has a corrected lens.

There is a chance you may need glasses for some tasks even after you adjust. For example, some patients need glasses to:

  • Read fine print
  • See more clearly in low light conditions
  • Obtain the best vision at intermediate distances, like at the computer

As your brain adjusts to the new visual information from the multifocal IOL, you may notice some rings around lights at night, which usually get better in time and diminish within six months or so. Most patients say these symptoms are not noticeable or bothersome and rarely affect their day or night activities. A small number of patients have night vision symptoms on an ongoing basis. Even when this occurs, these symptoms rarely affect tasks such as night driving.However, in rare instances, multifocal IOLs may make night driving more challenging than with standard or accommodative IOLs.

Our Locations

LaserVision was initially founded in Guildford, Surrey. Now with clinics in over 6 locations, we are able to treat the eye conditions of patients nationwide. This technology is available at:

As Seen On

The Guardian Logo
Laser Eye Surgery UK
The Times Laser Eye Surgery
At Home Magazine
Saga Logo
Surrey Advertiser Logo
laser eye surgery london
National Eye Health Week 2014

LaserVision is recognised by the following leading UK private medical insurers

Laser Eye Treatment Allianz
Aviva Logo
Laser Eye Correction Hospital
Bupa Medical Insurers
Eye Correction Treatment
Healix Logo
Vitality Insurers
WPA Healthcare

Professional Associations

Ziemer
Alcon
Schwind
Oculus
Zeiss
BauschLomb
AMO
Physiol
IPCL
STAAR Surgical
Rayner
AcuFocus
HeidelBerg Engineering
HSUK

Professional Bodies

ESCRS
Royal College of Surgeons Edinburgh
Royal College of Ophthalmologists
UKISCRS
ASCRS
ISRS Logo
CareQuality Commission
Request a ConsultationAttend an Event