Accommodating Simultaneous Vision Lenses

Acknowledging neuroplasticity and neuroadaptation as two key factors in selecting patients for a premium lens implant can greatly improve refractive outcomes, sensibly reducing the risk of unhappy patients, according to Pei-Fen Lin MBBS.

“What type of patient gives you the heebie-jeebies, the bad vibes that make you think, no trifocal for you?” Dr Lin asked.

When dealing with the realm of premium and, more specifically, trifocal lenses, she recalled her mentors’ wise words, warning her of the specific types of patients that can be troublesome to work with: the perfectionist and the hyper focused. However, so-called builder patients, thanks to their flexibility, can adapt more quickly to a trifocal lens.

How do these different personalities deal with refractive outcomes? It is widely known that 50% of patients implanted with advanced technology IOLs experience some form of dysphotopsia as well as reduced contrast sensitivity, but most people adapt, she said. Even patients with 20/20 outcomes sometimes complain.

One classic study reported that between 4% and 12% of patients implanted with simultaneous vision lenses (SVLs) retain some level of dissatisfaction, with 4.7% being so unhappy they will eventually ask for IOL explantation.¹ This leaves 45% of patients that do adapt, but what is the reason? According to Dr Lin, the answer lies in neuroadaptation.

The human crystalline lens is naturally monofocal; as a result, the entire optic system has evolved around this monofocality, with distance and depth of focus provided by binocularity and accommodation. Humans are the only species that ask their brain to switch between systems halfway through life, she noted.

For many people, vision is monofocal until the implantation of a multifocal cataract and presbyopic correction lens, forcing the brain to relearn and adapt to something that is not natural. This, however, is not an impossible task. As Dr Lin explained, this is where neuroplasticity comes into play.

Neuroplasticity is the ability to change the activity in the brain in response to intrinsic or extrinsic stimuli by reorganising its structure, functions, or connections. The same process can be involved in the rehabilitation or recovery of functionality following stroke, brain injuries, or amputations. Learning to use a prosthesis can initially feel clunky but eventually will become second nature.

To overcome dysphotopsia in multifocality, however, a patient needs to have a good level of neuroadaptation, a type of plasticity that refers to the decaying of neuronal activities in response to repeated or prolonged stimulation. According to a study from the NECSUS group, patient functional magnetic resonance imaging after three weeks from simultaneous binocular implantation of multi- and trifocal lenses showed an increase in blood flow in the areas of the brain dedicated to task planning, perceptual learning, and attention.²

Generally, this phenomenon returns to normal after six months, which is why Dr Lin suggested six months as the ‘magic number.’ If a patient complains of postoperative dysphotopsia and is dissatisfied with visual clarity, she recommends having them wait at least six months before doing something, giving the brain time to learn how to deal with this new setting.

To maximise the positive outcomes of this process, she suggests carefully selecting the patients that are eager to neuroadapt to multifocality. Neuroadaptation can be encouraged if the learning curve is smaller, such as in the case of patients who are tolerant to changes and highly motivated, she said. Patients who are hyper focused on fine details and rigid in their lifestyles will struggle with the process of adaptation. Therefore, a deeper neurological understanding can be especially useful for the ophthalmologist.

“It is our job to find the easiest way for the brain to adapt to a new technology you want to provide for your patients,” Dr Lin said. “Technology hopefully will advance in the future to help us do that.”

Dr Lin presented at the 2026 ESCRS Winter Meeting in Helsinki.

Pei-Fen Lin MBBS, MA (Cantab), PGDip, FEDIP, FRCOphth is Consultant Ophthalmic surgeon at Moorfields Eye Hospital NHS foundation trust, London. p.lin@nhs.net

1. Rosen E, Alió JL, Dick HB, Dell S, Slade S. J Cataract Refract Surg, 2016 Feb; 42(2): 310–328. doi:10.1016/j.jcrs.2016.01.014. PMID: 27026457.

2. Rosa AM, Miranda ÂC, Patrício MM, McAlinden C, Silva FL, Castelo-Branco M, Murta JN. J Cataract Refract Surg, 2017 Oct; 43(10): 1287–1296. doi:10.1016/j.jcrs.2017.07.031. PMID: 29120714.