Time to Move Beyond Monofocal IOLs?

Nowadays, monofocal IOLs are surgeons’ first choice regardless of the patient’s profile or the underlying clinical conditions; it is time to move forward and question this paradigm. Extended depth of focus (EDOF) or multifocal IOLs should be prioritised, as those are more likely to deliver higher rates of spectacle independence, according to Dominique Monnet MD, PhD.

“The reality is the monofocal IOL no longer fully meets the expectations of our patients. We are better off not considering monofocal IOLs as the first intention—but rather reserving their implantation for when we cannot do otherwise,” Dr Monnet said at the 2024 ESCRS Winter Meeting in Frankfurt.

Discussing the limitations of monofocal IOLs, Dr Monnet noted a recent survey of more than 455 French surgeons found 44% would select EDOF lenses for their own eyes compared to 40% who would prefer a monofocal lens.

“When we combine the results for EDOF and multifocal IOLs, we find that more than 60% of surgeons would prefer a presbyopia-correcting IOL (PC-IOL) implanted for their own cataract surgery,” he said. “And yet, we don’t give the same options to our patients.”

Enhanced patient expectations

Patient expectations are no longer the same in an era when cataract surgery has become a type of refractive surgery, noted Dr Monnet.

“First of all, we need to bear in mind that presbyopia is the primary cause of reduced quality of life in our patients,” he said. “Secondly, when we ask our patients their expectations just before cataract surgery, more than 83% of them say they are interested in no longer wearing glasses after cataract surgery.”

With options available to deliver higher rates of spectacle independence, the real paradox is the monofocal lens remains the most inserted implant in the world, far ahead of PC-IOLs, even in developed countries.

“This is clearly shown in the ESCRS Clinical Trends Survey where we see only a slight progression in the use of PCIOLs from 2016 to 2021,” he said. “We can deduce from the figures that monofocal lenses are still implanted in around 90% of cases.”

One of the ironies of recent IOL history is surgeons were encouraged to move away from spherical IOLs in favour of aspheric lenses, ostensibly to ameliorate the quality of vision and compensate for the spherical aberrations created by the cornea, Dr Monnet explained.

“Visual acuity and especially contrast sensitivity were better with aspheric lenses, particularly in mesopic conditions,” he said. “But we discovered that our patients lost depth of field, which was not a great surprise as we know there is an inverse relationship between the degree of asphericity in the optic and the depth of field.”

Industry solution

The industry solution was to develop an enhanced monofocal or monofocal-plus lens to induce some spherical aberration, thereby improving depth of field and intermediate vision.

“We consider our previous spherical lenses could probably be categorised today as a monofocal-plus lens, as they essentially achieved the same effect,” he said, adding the main limitation of the monofocal lens is it does not provide spectacle independence.

“It is not the best option for a patient who wants to become independent of glasses after cataract surgery. Even for uncorrected distance visual acuity, EDOF and multifocal IOLs perform better than monofocal IOLs.”

Although mini-monovision might be considered a viable option to compensate for presbyopia, Dr Monnet said the approach also has some limitations.

“There is still less spectacle independence compared to multifocal IOLs with monovision, and the loss of stereopsis is not always well tolerated by the patient,” he said.

Decision tree to orient choice

In his practice, Dr Monnet said he uses a decision tree for IOL selection based on patient motivation and clinical examination.

“The principle is to move away from the habit of considering monofocal as first intention,” he explained. “I classify my patients into three categories: very motivated, moderately motivated, or little or not motivated. After clinical examination, I implant either a multifocal or a multifocal toric IOL in a very motivated patient in the absence of any comorbidities. If there is a contraindication for the multifocal lens, I propose an EDOF lens for motivated patients. And if there is a contraindication for the EDOF, I propose a monofocal IOL.”

Dr Monnet concluded the enduring popularity of monofocal lenses could be ascribed to two factors: low cost and the absence of induced visual symptoms. However, lens solutions exist to correct presbyopia and should be offered if the patient fits the criteria.

“Compensation for presbyopia is based on a compromise between three factors: visual quality, depth of field, and photic phenomena, which must be adapted to the profile of our patients,” he said. “In the future, the monofocal lens could regain its interest with the advent of a functional accommodative lens.”

Dominique Monnet MD, PhD is an ophthalmologist at Cochin Hospital, Paris, France. dominique.monnet@cch.aphp.fr