Multifocal IOLs: The mix and match approach

The mixing and matching of refractive and diffractive multifocal intraocular lenses (MIOLs) to enhance vision in cataract patients is not a new concept. In fact, the theory was first pioneered and realised in 2000 by Uzeyir Günenc, MD of Dokuz Eylül University, Izmir, Turkey, who went on to present his first set of results at the 2003 congress of the ASCRS. So why is it that, back then, nobody really paid attention to this technique? The answer is simple; the idea at that time seemed quite bizarre and was something that many surgeons would never consider performing in their own practice. Three years on and armed with five-year data, the global ophthalmic community is now starting to pay attention.

This concept was brought to life when Dr Günenc realised that, although MIOLs with diffractive designs and refractive designs were favoured in his practice and, indeed, yielded successful visual outcomes and patient satisfaction, reduced contrast sensitivity and visual symptoms were occasionally reported. He hypothesized that every MIOL technology is not without limitations and that not one alone can offer a patient good near, intermediate and far vision, all at the same time.

A happy surgeon needs happy patients

With that in mind, Dr Günenc and his team enrolled 30 eligible cataract patients (40 eyes) into a prospective study, which was performed in his clinic between May 2000 and April 2001. The study assessed distance and near visual acuity, postoperative spectacle dependence, depth of focus, contrast sensitivity changes, presence of photic phenomena and patient satisfaction in eyes implanted with either the diffractive 811E CeeOn IOL (Pharmacia), the refractive Array IOL (AMO), or in patients implanted with both (one in each eye).

Of the study group, 10 patients had unilateral implantation of the diffractive IOL, 10 patients had unilateral implantation of the refractive IOL and 10 patients had bilateral surgery (one eye with the diffractive and the other with the refractive IOL). For consistency, Dr Günenc performed all surgeries.

At six-month follow-up, Günenc and his team noted more satisfactory outcomes in the bilateral sub-group, with 90% of patients reporting spectacle independence for near and distance tasks, i.e. daily activities. This ratio was 60% for the unilateral implantation sub-groups. Furthermore, 80% of bilaterally implanted patients voted "very good/excellent" for the results of the surgery.

Admittedly, before this technique is widely accepted, further support is needed in the form of clinical studies. There is still some uncertainty over whether mixing and matching two different MIOL technologies (refractive and diffractive) in the same patient is the best approach to provide binocular vision that is satisfactory at all distances. Further, concern over long-term risks and side effects that may be associated with this approach still remain. However, even with the older generation of lenses, Günenc was able to show excellent outcomes in patients at six months. He will also soon be reporting his long-term, five-year data with the technique, which also demonstrate improved visual performance, patient satisfaction, safety and efficacy.