comparison of four multifocal implants to compensate for ... ?· modern cataract surgery is a...
Post on 19-Aug-2019
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Visya – www.cliniquevision.com
M. ASSOULINE, L. BESSEDE Centre IénaVision, PARIS. Clinique de la Vision, PARIS. firstname.lastname@example.org email@example.com
Comparison of four multifocal implants to compensate for presbyopia during cataract surgery INTRODUCTION There are a number of different IOL models available for cataract patients that may differ in:
material (hydrophilic or hydrophobic acrylic, silicone, PMMA);
design (plate haptics or loop haptics);
optical properties (aspherical implants slightly improve night vision in younger subjects);
optional yellow filter (designed to protect the retina and the macula from the toxic effects of UV rays and blue light).
In practice, the visual performance of these implants depends mainly on their optical qualities (standard monofocal, aspherical, toric, multifocal). Recent advances in multifocal implant designs have revolutionized cataract surgery, offering patients a truly spectacle-independent postoperative life. Not only will they have the opportunity to have perfect distance vision, which is a typical feature of standard monofocal implants, but also excellent near vision at 35 cm (reading), and with the most recent implants, satisfactory intermediate vision at 70 cm (computer work, reading sheet music, using smartphone/tablet, etc.). However, an informal survey has revealed that while experts in the field and surgeons who implant more than 200 multifocal IOLs per year have adopted the latest-generation multifocal implants for 50 to 70% of their patients, most cataract surgeons, particularly those not performing LASIK surgeries on a regular basis, are very reluctant to use these implants routinely. Instead, they implant them sparingly and only in patients who specifically request these IOLs. This explains why multifocal implants still account for less than 6% of the French market. This figure is difficult to explain considering that 80% of patients have no contraindication to these implants and in light of their functional advantages in terms of quality of life.
Modern cataract surgery is a refractive surgery and must expand to include presbyopia correction:
for patients who have knowledge or experience with refractive laser surgery or intraocular cataract lenses;
for surgeons who regard it as a more sophisticated and rewarding personal accomplishment, as well as an opportunity to provide a remarkable medical service to patients who place their trust in surgeons;
and to match the competing options, since developing and adopting innovations to new implants is faster.
"Expert" surgeons who use multifocal implants widely in their practice:
have changed their approach to cataract surgery to a refractive one (no post- operative glasses, using toric implants, monovision, and relaxing incisions);
have realized the benefits that multifocal implants have on the medical service provided to patients;
offer the surgery to younger patients, from 60 years of age for instance, but without upper age limit (up to 85 years old);
use multifocal implants to develop their surgical practice, thus gaining a competitive advantage by improving the medical services they provide;
Patients are more and more demanding:
if they've heard of presbyopia or astigmatism correction as part of cataract surgery (media, internet, neighbors, friends and family, or in the waiting room);
if they don't understand why they still have to wear eyeglasses or contact lenses permanently after surgery while their neighbors or friends and family don't have to after their operations;
and are also very grateful to surgeons for taking the time to choose the best visual correction for their specific needs.
THE SWITCH TO MULTIFOCAL IMPLANTS – WHY AND HOW? Multifocal implants are a better way to correct:
astigmatism if a toric version is available;
patients' refractive expectations, whether stated explicitly or not. They also improve the functional results of cataract surgery:
better uncorrected acuity;
enhanced visual autonomy;
better quality of life. Finally, they improve patients' impression of the quality of medical service provided:
satisfaction because of personalized care;
appreciation of the surgeon's expertise and the results;
boost the surgeon's brand and act as a recruiting agent.
STRICTER QUALITY PROCEDURES APPLY TO MULTIFOCAL IMPLANTS Switching to and prescribing multifocal implants requires a stricter approach to quality, especially when it comes to your training and communicating with patients. All steps of a successful "conversion" to multifocal implants are equally important because the promises made to patients limit the surgeons' margin of error.
Understand the optics and PhysIOLogy of vision relating to multifocal implants thoroughly.
Be convinced of the benefits of these implants, both for your patients and yourself.
Talk to practitioners who are used to multifocal implants.
Attend one of their pre- and post-operative consultations.
Have a detailed discussion with patients who have benefited from multifocal implants as well as patients who have not.
Learn about the real costs of post-operative prescription eyeglasses.
Integrate information on multifocal implants into the standard information given to patients.
Systematically discuss multifocal implants with each patient.
Highlight the advantages in terms of effectiveness and comfort.
Reassure patients that the implants are perfectly safe.
Mention the rare contraindications, screened during pre-operative tests.
Before the operation, do not evade the postoperative quality of vision, the need for learning (neuro-adaptation) and the potential need for adjustment (less than 0.5% of cases) for perfect refractive results.
Be clear on financial questions.
Offer additional information before the patient decides.
Give patients time to consider the options and make up their own mind.
Apply the necessary pre- and post-operative protocols properly.
Support patients after surgery for as long as is necessary for perfectly satisfactory results.
AVAILABLE MULTIFOCAL IMPLANTS Multifocal implants can be divided into 5 groups based on the design of their optic (Fig 1):
single diffractive bifocal (apodized or not): e.g. ATLisa Bifocal (Zeiss);
double diffractive (trifocal): e.g. FineVision (PhysIOL);
diffractive/refractive (improved depth of field): e.g. Bi-Flex 677M (Medicontur);
concentric multizone refractive: e.g. ReZoom (AMO);
sectorial aspherical refractive: e.g. Lentis Mplus (Oculentis / Topcon).
Diffractive multifocal implants include a microstructure of concentric steps similar to Fresnel lenses used in flexible flat magnifying lenses or in lighthouse lenses.
In diffractive optics, the height of the steps determines the distribution of energy between the distance and near focal points, while the width of the steps defines the power of the addition.
In a conventional diffractive implant, the optic is bifocal for distance and near vision. There is thus insufficient light intensity at the intermediate vision point of focus, impeding many important activities that take place between 60 cm and 1m (computer or tablet use, sculpture, painting, smartphone, reading sheet music). The benchmark bifocal implant is the ATLisa IOL (Zeiss), which is the most widely used in France. This classic diffractive implant optimizes light energy distribution depending on pupil diameter, due to the apodization process (the steps decrease in height towards the periphery). When the pupils are wider, far vision is dominant. With narrow pupils, near vision prevails. The diffractive steps are also "softened" to limit halo effects. The most recent diffractive models have tried to remedy the shortcomings in the intermediate range while retaining excellent uncorrected near vision. They are usually preferred for the non-dominant eye. IOLs utilizing two different principles are available. >>> The FineVision implant (PhysIOL) features a double diffractive network so that light energy can be recovered from the diffractive harmonics (secondary foci) to focus about 11% of light on the intermediate focus point. This principle is used in the trifocal version of the ATLisa Zeiss implant as well.
Refractive 5 zones
Diffractiva Human Optics
Transitional Bitoric MiCS
Diffractive Aspherical Apodized
Lentis M+ Oculentis Refractive Aspherical
Biflex M Medicontur Diffractive Apodized
Fig. 1: Multifocal IOLs available in France
Bi-Flex M ReStor Tecnis M Flex ATLisa Fine Lentis Mplus
Diffractive x X x x x
Apodized x X x
Aspherical x X x x x x x x
x x x x x x
MICS x x x x
SE 360° x x
Toric option coming