By Simon Wyatt
As an industry, from the material manufacturer to the surgeon, our aim is to provide the patient with the best possible visual outcome following cataract surgery. It is very much a “team effort”. That said, it is generally the finished IOL that receives all the plaudits, or indeed criticism, once surgery is complete. Are we not wrong in also considering the important part the material, and indeed the delivery system, plays in achieving that desired “successful outcome”?
With this thought in mind, I feel it is perhaps time raise the profile of the less visible, but equally important, contributors to the team.
Contamac’s CI26 is by some way, the leading hydrophilic material in the global market today, with over 70 million IOLs implanted in eyes around the world. It is the ONLY hydrophilic material from which IOLs are manufactured that are approved for sale in the USA. Given that we all recognise the rigours of FDA approval, this is an achievement which should not be overlooked. Regulatory approval in China is equally as challenging and the CI26 is the material which dominates hydrophilic IOLs approved in China today. The history, quality, safety and consistency of our material, provides the best platform for any hydrophilic IOL. The best lens design in the world will be consigned to history very quickly if it’s core, the material, fails.
So, what makes the CI26 the stand-out performer?
- Guaranteed consistent quality of the material
- Fast but controlled, unfolding in the eye
- Flexible but strong, allowing small/micro incision, 1.8mm
- A 20 year history of safety
I increasingly hear of the demise of PMMA, although personally I think it has many years to run, with hydrophilic becoming the new PMMA. For many, PMMA remains the best and safest IOL material to date, but as technology develops and post-operative care becomes a burden that no State can afford, it’s decline is perhaps inevitable. So as the “new” PMMA, can we expect to see hydrophilic IOLs decline in price still further. Of course there are a number of hydrophilic materials available and you could of course, seek independence and a lower material price, and “cook up” your own. The choice, but of course also the risk, is yours. To put at risk the time and investment, and of course the huge regulatory burden, you have in your lens design by “saving” on material cost, is a big gamble.
Has the world now gone hydrophobic? Like many of our long-standing customers, we too have had to move into the hydrophobic arena. I’m not exactly sure of the main driver for this. It may be driven by price, as to a large degree hydrophobics do seem to obtain a higher price. It may be a concern over PCO, as hydrophobic material appears less prone to this. Perhaps it is a case that today, most manufacturers have found a method to produce a cost effective hydrophobic IOL. In some cases, it may also be a cursory review of the market, which clearly sees hydrophobic, as the majority material. Whatever the reason or combination, the same rule applies, material choice matters.
Hydrophobic materials for a long time, faced criticism over slower unfolding and less flexibility (therefore larger incision size). Manufacturing a high-quality optic is a challenge given the soft nature of the material and once achieved, polishing is equally difficult. Our HI56, semi-finished product, produced with our partners Innovalens on the unique moulding technology they developed has, I believe, addressed many of these criticisms and challenges. The material unfolds in under 20 seconds at 24 degrees, 5-7 seconds at 28 degrees and an RI of 1.56 facilitates a thinner lens, so smaller incision. To many however, it is the quality of the optic that is the stand out feature. A cast moulded optic provides a clarity I do not believe can be achieved through the combination of lathing and polishing, and the square edge remains sharp and not rounded, through hours or days of polishing.
I cannot conclude on hydrophobic without mentioning the “glistening” word. This now seems to be the default position on deciding on material choice and the determining factor on how good an IOL is perceived to be. Of course, we must all strive to produce the best lenses possible for the patient, but am I the only one who feels this discussion is getting a little out of control? Hydrophobic materials are prone to glistening. To a large extent, the level of glistening can be determined by the water content within the formulation. The more water over 1%, the more likely glistening will be evident, over 2% and one gets closer to the apparent holy grail of “glistening free”, at closer to 5% glistening free is achieved, but the hydrophobic IOL is then packaged wet.
There is no standard test to determine glistening and ironically the purpose of these tests is to deliberately force glistening into the material. All other tests we undertake are designed to assess the performance and safety of the IOL once in the eye. Why do we now seek, not to try and asses the likely condition in the eye, but instead create a “league table” showing to what extent glistening can be forced into a material, in some cases under such extreme conditions, that were the patient’s eye to experience this level of volatility and temperature, glistening of his/her IOL would be a very minor concern.
We are not seeing thousands or even hundreds of lenses explanted due to patient complaints of glistening. For me, that is evidence enough, based on actual conditions and performance in the eye.
I have tried to demonstrate the need to consider carefully the choice of material, as this is a fundamental part of the finished lens. But even when our job is done, material and lens designs can suffer if delivery into the eye is problematic. We should also therefore recognise the other “team member”, the injector system.
“We have to give away our injectors” is a phrase I hear more and more. I do sympathise. With prices continuing to fall you need to protect what little margin is left, so savings on injectors seems to make sense. It is relatively cheap to have a mould made for your injector and cartridge, and keep costs down, BUT does it really make sense to compromise the integrity of your lens by saving a few cents on the delivery system. Your lens is judged once safely in the patient’s eye, and a disastrous delivery may well rebound on the lens or even the material!
The Ergotouch injector system is manufactured and designed to ensure an efficient and most importantly, safe delivery, of the IOL into the eye. For the injector itself, some of the key benefits are as follows:
- Complete and accurate alignment between the plunger and injector body, ensuring smooth transition of the lens through the injector and cartridge.
- Total visibility of the lens whilst passing through the injector.
- An “anti-slip” grip
- A robust injector body, with an ergonomic design for easy handling
- A “locking design” to avoid any possibility of the cartridge “ejecting” during surgery.
- Designed for both mono and bi-manual injection.
The cartridge is perhaps even more important than the injector itself and with this aspect, safety and control are critical. The cartridges, in sizes 1.8, 2.0, 2.2, 2.4 and 2.6, are provided with GMS or a unique coating. Key features are:
- High quality manufacturing, ensuring completely smooth inner surface and “clean” cartridge tip, to avoid scratching of the lens.
- High quality medical grade polypropylene material, to avoid the cartridge splitting.
- Carefully controlled GMS additive, to avoid residue on the lens.
- Locking cartridge clip, to ensure lens is securely loaded
- For the coated cartridge, a unique coating, aiding delivery and without leaving any residue.