IOLs: What Every Surgeon Needs to Know | Ep. 2: Enhanced monofocal IOLs

IOLs: What Every Surgeon Needs to Know is an editorially independent video and podcast series from Ophthalmology Times, hosted by Douglas D. Koch, MD, Professor and Allen, Mosbacher, and Law Chair in Ophthalmology at the Cullen Eye Institute, Baylor College of Medicine in Houston, Texas. In this episode, Koch is joined by Karolinne Maia Rocha, MD, PhD, Professor of Ophthalmology, Melosi Endowed Chair, Director of Cornea & Refractive Surgery, and Fellowship Director of Cornea & Refractive Surgery, Storm Eye Institute, Medical University of South Carolina in Mount Pleasant, South Carolina.

Together, they explore the optics behind enhanced monofocal lenses, break down patient selection criteria, and discuss strategies for setting realistic expectations before surgery.

Defining the enhanced monofocal category

Enhanced monofocal IOLs represent a relatively new lens category that sits between standard monofocals and full-range refractive lenses. Rocha explains that although these lenses remain classified within the monofocal category, their anterior or posterior surface geometry is modified to extend depth of focus without introducing the diffractive rings associated with multifocal designs. “It’s basically the lenses don’t have that perfectly spherical anterior surface of the lens,” she says. “It’s what we call high-order asphere.”

Among the currently available enhanced monofocal lenses in the US, three distinct optical approaches are represented: modification of the anterior surface curvature, curvature changes on the posterior surface, and the use of controlled spherical aberration to extend depth of focus.

Koch notes the breadth of optical engineering these three designs represent. “We’ve come at it from the front, we’ve come at it from the back, and we’ve come at it from a different direction,” he observes.

Clinical performance and patient benefit

Both surgeons describe the functional benefit of enhanced monofocals as extending usable vision into the intermediate range, particularly relevant for patients whose daily activities center on computers and smartphones. Based on available clinical data, Rocha notes that these lenses provide approximately 1 additional line of near vision at intermediate and near distances on average. However, she cautions that binocular summation can amplify the effect: “When we’re measuring binocular, we know patients, they see 1 line better.”

The category is particularly well suited to patients who are not candidates for full diffractive technology including those with a mild epiretinal membrane, early drusen, or other conditions that warrant a more conservative optical approach. “I think it’s definitely [a] great option for patients with normal eyes or patients that are not candidates for diffractive technology,” Rocha says.

Setting expectations and surgical planning

Both surgeons emphasize restraint when counseling patients preoperatively. Rocha’s approach is to underpromise and overdeliver: “I never tell patients about it in advance because I never know who’s going to get it.” Koch shares the same philosophy, particularly regarding the dominant eye first strategy. If a patient achieves strong distance vision with meaningful near benefit from the first eye, he may elect to use a similar lens in the fellow eye rather than escalating to monovision or a trifocal.

Rocha typically targets plano or a mild myopic offset—approximately −0.5 to −0.75 D in the non-dominant eye—to optimize the extended range while preserving functional distance acuity. She notes that targeting −0.75 D in the nondominant eye still yields distance acuity in the range of 20/25 to 20/30, allowing patients to benefit from the extended range without meaningful distance compromise.

Patient selection and contraindications

Corneal topography is central to Rocha’s selection process. Patients with a history of myopic LASIK with a small optical zone carry excess positive spherical aberration, making a lens with negative spherical aberration a more appropriate choice. Irregular corneas may call for an aberration-free design. She avoids enhanced monofocals in eyes with significant coma, such as those with keratoconus, where an aberration-free lens is preferred.

Koch adds that occasional reports of reduced quality of vision with these lenses—which he has not personally encountered—reinforce the importance of careful corneal assessment. “The irregular corneas, something isn’t sitting quite right, and certainly corneas with a lot of already negative spherical aberration or a lot of coma, maybe you’re better off with a more uniform optical surface,” he says. Both surgeons agree that the category is, in Rocha’s words, “very forgiving” within appropriate indications.

Rocha closes by framing enhanced monofocals as a premium option for eyes not suited to full-range lenses. “I think the patients are very happy with this technology,” she says.

Douglas D. Koch, MD

E: [email protected]

Koch is Professor and Allen, Mosbacher, and Law Chair in Ophthalmology at the Cullen Eye Institute, Baylor College of Medicine in Houston, Texas.

Karolinne Maia Rocha, MD, PhD

E: [email protected]

Rocha is Professor of Ophthalmology, Melosi Endowed Chair, Director of Cornea & Refractive Surgery, and Fellowship Director of Cornea & Refractive Surgery, Storm Eye Institute, Medical University of South Carolina in Mount Pleasant, South Carolina.