An IOL is an Intra-Ocular Lens. First concept for IOL's goes all the way back to 1940's London, Where eye surgeon, Sir Harold Ridley developed and implanted the very first IOL in the world.
You would think that the IOL idea would have rocketed, but alas NO - the medical establishment at the time rejected the concept and so the story of the IOL was almost forgotten until the 1970's when a group of young eye surgeons decided to re-invent the IOL. The rest as they say is history!
Your eye has two major focusing elements. First the cornea which provides around 2/3 of the focusing power of the eye. Second the natural lens which provides the rest. During cataract surgery - the clouding natural lens is removed and so with it goes the roughly 1/3 of the focusing power of your eye. Without an IOL, it is very likely that your eye would be heavily under focused. This typically means that cataract extraction without lens implantation would leave the average person very 'long sighted' or hyperopic.
You may remember people of your parents or grandparents generation wearing very heavy, thick glasses to be able to see properly after old fashioned cataract surgery - well this is the reason why IOL's became an essential part of cataract surgery. In a nutshell to provide the missing focusing power.
The safety of IOL's has now been established beyond any doubt and all around the world cataract surgery should always involves the insertion of an IOL.
Zeiss’ AT-LARA 829 MP EDOF IOL’s
BIFOCAL intraocular lenses produce TWO focal points (FAR and around 1/3m (33cm) only.
TRIFOCAL intraocular lenses produce THREE focal points. Typically FAR, INTERMEDIATE 2/3m (66cm) AND CLOSE range 1/3m (33-40cm)
Zeiss AT-LISA Trifocal Toric (top) and Non toric IOL’s
Two different designs of monofocal toric IOL’s. Top is ‘C loop’ haptic and bottom is plate haptic design. The line marks on the optic area denote the axis of the astigmatic power.
Effect on vision of even mild degrees of astigmatism
How accomodation works
A double optic accomodative IOL design (withdrawn)
It’s certainly true that IOL designs have proliferated over the last 25 years or so – that is a good thing! But of course, it does make it all the more important that as a prospective patient who may be considering Refractive Lens Exchange or Cataract Surgery, you do your own research and consult a surgeon who has peerless experience of using many different types of lens implants. Mr Rehman is passionate about giving his patients as much choice as possible when it comes to selecting their IOL and he is exceptionally well positioned to help navigate you through the decision-making process so that you have the very best chance of meeting the goals you wish to achieve.
In my conversations with many hundreds of patients every year, I get asked this question quite often! There is no such thing as the ‘best IOL’ - in other words different types of IOL’s are designed to achieve different things. Very few independent head to head clinical trials exist comparing similar types of IOL’s. As an experienced surgeon, I like to workwith IOL companies with a long and established track record of design andinnovation – such as Zeiss, Rayner, Alcon, Johnson & Johnson. The key issue is for you and your surgeon to agree on your major objectives and priorities and then to be guided by your surgeons’ personal experience on which IOL’s to select.
Yes it is! Given that different IOL’s provide different optical properties, it is indeed possible to select IOL’s with complimentary properties in order to deliver a particular type of visual outcome. One example is a scenario where we sometimes select a TRIFOCAL IOL for one eye and an Extended depth of focus IOL for the fellow eye. These two types of IOL often work very well together in a supportive, complimentary way to provide an even greater prospect of spectacle independence for close range, intermediate (VDU work) and far distance. That said – our default position is to use the same type of IOL in both eyes – e.g Trifocal / Trifocal or EDOF / EDOF as this tends to work very well for the majority of patients that we treat.
Unfortunately, with the best will in the world and even with ‘perfect surgery’ not everyone treated with IOL surgery will achevie the results that they hoped for. This is not by any means common – and in my experience significant dissatisfaction is very uncommon – with around 98% of patients reporting satisfaction in surveys. For those who do not meet their goals, occasionally there is a clear path towards achieving theirgoal – this may be with some additional vision correction treatment – typically Laser vision enhancement with LASEK/PRK or LASIK can be considered in many situations. Make sure you ask your surgeon or clinic whether there would be an additional charge for this and also that they will be able to offer this service for you – many do not or will not. Rest assured, in my practice most of our patients opt for the ‘Refractive package’ and thus we are easily able to offer this service where its required. A secondary option is even less commonly utilised, which is IOL exchange – something I outline below.
Yes – but it is not something that we undertake very often at all – in fact in my practice, IOL exchange is something we consider in less than 0.3% of our patients – this is a strong reflection of the overall success of our treatments as many clinics report significantly higher rates of IOL exchange. IOL exchange surgery is a little more complex than primary implantation but is something that can be considered in the following circumstances:
IOL exchange is thus perfectly feasible but is not an option that should be undertaken lightly due to additional risks. Equally please ensure that your surgeon is capable of IOL exchange as a surgical procedure – not all
Technically it may be – but we would strongly advise against changing an IOL just to upgrade to a ‘better’ IOL in the future. IOL exchange as indicated above is a more complex procedure and is something that we utilise in highly specific circumstances only. We would like to think of your primary IOL as the first and only IOL you will need
Forever! IOL’s are designed to stay inside your eye permanently and with a extremely low risk of significant problems arising with the IOL itself (such as lens implant clouding) we fully expect the IOL to last a full lifetime
Essentially NO. IOL’s are made out of materials which are highly biocompatible with the eye, this means ‘rejection’ in the true sense of the word Is extremely unlikely
No! The key parameters that lead to an eyesight prescription are the following:Focusing power of the cornea
Focusing power of the natural lens (or IOL)
Length of eye from front to back
Its assumed that the focusing power of the cornea is largely stable after middle age as is the length of the eye, this means that once an IOL (with a fixed power) is positioned inside the eye to replace the natural lens (which often changes a lot from middle age onwards) – we have a theoretically very stable situation with respect to your post-surgery eye prescription outcome. This is the reason why we expect your eye prescription (which should be close to zero post op) remains stable on a long-term prospectus
The commonest treatment required in patients who have had IOL implantation surgery is YAG Laser Capsulotomy. This is required in around 10-20% of patients within a 2-5 year time frame post op. This treatment is required if the capsule membrane within which your IOL is positioned starts becoming a little cloudy (called PCO – posterior capsular opacification). PCO occurs as a result of cell ingrowth onto the capsule behind the central area of the IOL. When this occurs, your vision may start going a little cloudy once again. The good news is that YAG laser capsulotomy is a simple, routine outpatient procedure – taking just a few minutes. It is painless and highly effective in creating an opening in the capsule behind the IOL. Once the capsulotomy is created, it is extremely unlikely to recur meaning that this is generally a once only procedure. One point I would suggest patients seek clarity on is the funding position of YAG laser treatment. In my practice, the refractive package covers for the possibility of YAG laser being performed if it arises within a period of twelve months post op. Many clinics do not have such cover, so please be aware of this possibility in the future.
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