Refocus on Multifocals

Technological improvements in lens design have improved outcomes with multifocal intraocular lenses (IOLs) in terms of spectacle independence, but patient selection lies at the core of their successful use, Orkun Müftüoğlu MD told an ESCRS webinar.

“You need to choose the lens that serves your patient best,” he said. “Discussion is the most important part of the surgery.”

Professor Müftüoğlu noted that a meta-analysis of peer-reviewed publications of studies of multifocal intraocular lenses following cataract and refractive lens exchange involving 8,797 eyes showed 80% of patients achieved spectacle independence for distance and near vision. In more recent studies with the newer trifocal IOLs, that figure has been closer to 100%. Patient satisfaction has ranged from 60% to 100%, with most of the recent studies having close to 100% satisfaction rates.

When assessing patients’ suitability for a trifocal IOL, the surgeon must ensure their expectations are realistic and they understand they may need reading glasses, he emphasised. In addition, the surgeon must assess, based on lifestyle and profession, whether their need for quality of vision exceeds their desire for spectacle independence.

In a consensus statement, the European School for Advanced Studies in Ophthalmology (ESASO) issued key recommendations for employing a diffractive multifocal IOL. They include a potential postoperative visual acuity better than 0.5, keratometry between 40.0 D and 45.0 D, a pupil larger than 2.8 mm under photopic conditions, and root mean square (RMS) of higher order corneal aberration less than 0.5 μ for a 6.0 mm pupil. The statement also recommends considering monofocal or non-diffractive IOLs for patients with coexisting eye disorders.

Prof Müftüoğlu noted that patients tolerate ametropia less well with multifocal IOLs than with EDOF IOLs or monofocal IOLs. Therefore, biometry with modern tools such as swept-source optical coherence tomography and fourth-generation IOL calculation formulas is essential. In addition, treatment of astigmatism when present is mandatory and should be less than 0.5 D cylinder.

Following trifocal IOL implantation, it can take several months for patients to achieve final postoperative visual acuity. They must first undergo a period of perceptual learning to adapt to the multifocal optics, after which it appears to become second nature, he noted. A functional magnetic resonance imaging study investigating neuroadaptation to multifocal IOLs showed that early in the neuroadaptation phase, patients had increased activity in the parts of the brain associated with visual attention, goal-directed behaviours, procedural learning, and effortful cognitive control. However, by the sixth month of follow-up, that activity had returned to baseline.

He noted the rate of IOL exchange due to neuroadaptation failure is less than 1%, and that rate has continued to go down with the advent of more advanced diffractive multifocal IOLs. However, IOL exchange does not always fix the problem, with 23% of patients reporting dissatisfaction with the results and most saying they would not have undergone the exchange if they had it to do over again.

Prof Müftüoğlu presented his paper at an ESCRS eConnect Webinar, “Evidence-based overview of current premium IOL technologies.”

Orkun Müftüoğlu MD, FEBO is based at Koc University School of Medicine, Istanbul, Turkey. orkun.muftuoglu@gmail.com