Expertise and knowledge: essential tools in cataract surgery with toric IOLs

A proper evaluation of the complex problems related to cataract surgery with toric IOLs requires high records of simple and complex cases, filtered by critical knowledge. For this reason we asked the opinion of Professor Ozana Moraru, who is well  known even in Italy, as she has been speaker at many Italian ophthalmological meetings.


Who is the patient of cataract refractive surgery in the second millennium: expectations, literacy, life-style?
Nowadays the patients are more willing to be spectacle independent after their cataract surgery and moreover, they ask for this spectacle independence, even if they don’t have cataract – meaning that they require a refractive surgery solution for their ametropia. Because of these high expectations, the IOL industry and the refractive surgery, generally speaking, had to have a huge development in the last fifteen years or so.
There are possibilities for the astigmatism correction, via a Toric IOL implantation, or for the presbyopia correction, via a multifocal or trifocal IOL, and for both presbyopia and astigmatism, via multifocal toric or trifocal toric IOLs and moreover, there are possibilities for refractive “fine tuning”, by using Laser technology to adjust post-operative unwanted residual refraction. For bigger refractive surprises, or for patients where the Laser corneal surgery is not a good option, there is the Add-on IOL technology developed in the last years, which helps in reaching the desired post-operative refraction, the Plano refraction.
Thus, mastering all these new devices and tools, the surgeon is able to offer to his/her patients, complete spectacle independence, which is so required nowadays, when patients are more and more demanding, according to modern lifestyles.

Mini-incision and preloaded injector: what is their importance for the surgical outcomes?
The smaller the incision, the less the induced astigmatism, but is there an inferior limit? Practice and studies have shown that an incision smaller than 1.8 mm does not really influence the astigmatism.
So, it is not really important from induced astigmatism point of view, to perform an incision smaller than that. On the contrary, the bigger the incision, the bigger – and, in the same time, the more variable – influence on the induced astigmatism.
As a logical consequence, a small incision, between 2.2 and 1.8 mm, insures a smaller and less variable and more controlled astigmatism – a mandatory
requirement in toric IOL implantation, for a very good post-operative refractive outcome.
In the same time, even without a toric IOL implantation, MICS cataract surgery insures safer surgical profile: working in a close system, you have better stability during surgery (in terms of anterior chamber depth, IOP, posterior capsule stability) and, in the same time, there is less risk for intraocular infection. But again: the incision should not be that small, that it is forced and enlarged during the surgery or during the IOL implantation, putting at risk the IOL integrity and/or the safe incision closure with self healing, with the need for suture, at the end of the procedure!
One or more sutures on the incision will determine a big astigmatism and will completely disturb the initial calculations concerning the emmetropic target, because the SIA is very high and unpredictable in these cases!
Preloaded IOLs are much safer from this point of view: no manipulation of the IOL and no contamination of the IOL. In my practice I noticed that there is a small learning curve in their implantation, with some insignificant issues in the IOL delivery in the AC, but also with some enlargement of the incision done by the implantation itself.

Ph. 1-2: Two different toric IOLs blocked in an 1.8 mm incision, leading to incision traumatic enlargement, with increased and incontrollabe SIA and maybe lack of self-sealing at the end of the procedure, needing for suture.

Ph. 1-2: Two different toric IOLs blocked in an 1.8 mm incision, leading to incision traumatic enlargement, with increased and incontrollabe SIA and maybe lack of self-sealing at the end of the procedure, needing for suture.

For example, we shall present at the ESCRS Congress in Copenhagen a paper with a comparison of implantation of AcrySof IQ IOL (Alcon) with three different devices (Cartridge type “D” in a Monarch injector, Autosert System and Preloaded Ultrasert System), where we compare three parameters: easiness of implantation via wound assisted technique (with possible complications during implantation), duration of the implantation and enlargement of the incision by the implantation itself.
It seems that, at least in my hands, the preloaded AcriSof IOL system (UltraSert) enlarges a bit more the incision, and this observation and result can be important when we target the emmetropia, especially for the preloaded Toric IOLs, where we shall need to modify the Surgical Induced Astigmatism (SIA) Vector value in our toric calculation.
But, despite the initial learning curve and some incision enlargement, I think that the preloaded IOLs are safer for the surgery outcomes, at least from the safety reasons, due to lack of IOL manipulation.

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Editore - venerdì, 16 settembre 2016
Area Chirurgica