Evaluating the EDOF Effect

Extended depth of focus (EDOF) IOLs have overcome some of the issues associated with multifocal IOLs while providing enhanced spectacle independence over a wider range of vision compared to classic monofocal lenses, according to Myriam Böhm MD.

“The EDOF lenses help to minimize optical phenomena such as halos and glare, which are common to diffractive bifocal or trifocal lenses or refractive IOLs with a higher near addition of +3.0 D,” she said. “However, EDOF lenses do not provide complete spectacle independence, and glasses may still be required for near vision for many patients.”

Historically, there were two options for presbyopia correction—monofocal or multifocal IOLs—with benefits and drawbacks for each category of IOL. Monofocal IOLs provide focus at one distance only with a loss of depth perception and compromised intermediate vision. Multifocal lenses offer multiple focal planes for a full range of vision but with an increased chance of visual disturbances and reduced contrast sensitivity, she said.

The development of EDOF lenses has been driven in recent years by a change in patient lifestyle and priorities, said Dr Böhm, with a lot more tasks now performed at intermediate distances (computers, phones, driving dashboards, etc.).

“There was a clear gap in the market EDOF lenses could address by providing improved intermediate vision, reduced visual disturbances, and better contrast sensitivity,” she said.

In essence, the EDOF lens delivers an elongated focal point for a continuous range of focus, avoiding images overlapping and therefore (theoretically) eliminating the halo effect, Dr Böhm said.

She explained there is no universal agreement on the definition of an EDOF lens, even though the American Academy of Ophthalmology issued a consensus statement in 2017 of criteria that could be used to evaluate an EDOF IOL’s performance

under photopic, mesopic, and glare conditions. “However, there are no criteria on visual disturbances in the consensus statement,” she said.

The benefits of EDOF lenses include excellent distance visual acuity, improved visual acuity in the intermediate range between 60 cm and 100 cm, and functional near visual acuity. The drawbacks are that reading glasses are often required, with a potential decrease in contrast sensitivity and optical quality and photic phenomena that depend on the lens design implanted.

There are several sub-categories of EDOF lenses, including IOLs based on spherical aberrations (Sifi Mini Well Ready, Wichterle IOL), pinhole effect (Acu-Focus ICL, Xtrafocus Pinhole Implant), hybrid EDOF and multifocal designs (EDEN, Finevision Triumf Pod, Tecnis Synergy), multifocal and low-power addition lenses (Lentis Comfort, AT Lara), and those with a modified central optical profile (Eyehance Tecnis, AcrySof IQ Vivity, etc.). All of these approaches have their strengths and weaknesses, Dr Böhm said, and no one lens will satisfy the requirements of all patients.

Dr Böhm presented at the 2024 ESCRS Winter Meeting in Frankfurt.

Myriam Böhm MD is an ophthalmologist at Goethe University Frankfurt, Germany. myriam.boehm@kgu.de