Monofocal, multifocal or accommodative IOL: which is best?

Among the different IOL options for presbyopia, monofocals are probably by far the most practically used ones said Thomas Neuhann. He added that competing options must be able to beat an already high level of success and patient satisfaction.

Dr Neuhann was the first of three speakers talking about IOL options for refractive lens exchange (RLE). Examining the case for monofocals, he said the presbyopic options for monofocals included monovision, astigmatism and low myopia.

In monovision, one eye, usually the dominant, is corrected for distance while the other is corrected for near, and this technique is gaining acceptance. In astigmatism one meridian can be corrected for distance while the other is corrected for near.

"In myopia, individual patients with spherical myopia of around -1 D can see approximately 20/30 at distance and approximately 20/40 at near, with perfect intermediate vision," he said, noting the phenomenon is under explored and often spontaneously reported by patients.

He added some practical pearls. "If you can simulate it, you must simulate it. Not just for five minutes, you must try for days or even one or two weeks. Also you should never give a patient who is used to monovision a bifocal IOL and don't correct astigmatism if it is used preoperatively for near."

Thomas Kohnen, arguing the case for multifocals IOLs (MIOLs), said pros included the optics, which offer permanent correction for distance and near vision. Furthermore, they are based on the monofocal IOL concept so there is long experience on the different designs. He added that there is low posterior capsular opacification (PCO) as a result of sharp edge designs and retinal complications are rare, if compartments are maintained.

Among the cons was the fact that exact biometry is necessary, though there is the possibility to correct residual refractive error using an excimer laser, for example. Another disadvantage is optical phenomena like glare and halos, which have been reduced but not eliminated. Finally, the long-term effect on diminished macular function is not yet known.

Accommodative IOLs have some cons too. John F. Doane offered his personal opinion that one size does not fit all, but he suggested an intermediary step might include having more than one plate length on IOLs. "Long term accurate preoperative prediction of capsular sulcus-to-sulcus dimension may develop allowing surgeons to fit IOL length to the patient," he said.

Nonetheless, accommodative lenses can achieve some excellent results and these are improving all the time. Furthermore, there is enormous industry interest in this type of IOL. "The concept first appeared in 1989 and the FDA only began investigations in 2000. We've learned a lot, but there's a lot more to learn," he said.

Ophthalmology Times Europe reporting from the XXIV Congress of the ESCRS, London, 9-13 September, 2006.