Expanding the range of vision with monofocal IOLs

(Image Credit: AdobeStock/Mohammed)

Reviewed by Kamran M. Riaz, MD

During a recent Ophthalmology Times Case-Based Roundtable, Kamran M. Riaz, MD, discussed expanding the use of enhanced monofocal IOLs in clinical and surgical practice beyond their use in conventional cataract surgery. He discussed 3 cases of “out-of-the-box” treatments. Riaz is a clinical professor, Thelma Gaylord Endowed Chair in Ophthalmology, and vice chair for clinical research at the Dean McGee Eye Institute, University of Oklahoma, Oklahoma City.

Monofocal IOLs

“Monofocal IOLs provide excellent distance vision, but patients still need intermediate and near vision correction,” Riaz said. Recently, technological advances in IOLs have resulted in the availability of enhanced monofocal IOLs, or monofocal plus IOLs, that provide the same distance visual acuity (VA) as the traditional monofocal version but also improved intermediate VA (IVA) for numerous activities—for example, reading tablets and viewing the car speedometer. Although nontoric monofocal plus IOLs are not “premium” IOLs, they allow patients to have improved IVA for these functional activities.

Several such lenses are commercially available. The most popular are the Tecnis Eyhance IOL from Johnson & Johnson Vision and the enVista Aspire IOL from Bausch + Lomb.

The Eyhance is built on the same platform and base geometry as the Tecnis ZCB00 lens and is designed to have continuous power changes from the periphery to the center, facilitating improved intermediate vision without glare, halos, and starbursts. Riaz explained that the lens uses a higher-order asphere to create slightly more plus power in the center of the optic. The photic phenomena are like those of the ZCB00 lens, and the modular transfer function (MTF) values in scotopic vision are superior to some of the other monofocal IOLs that are commercially available.

Another advantage of the Eyhance lens is that it functions well even in low light with a larger pupil, unlike other lenses that often may have a reduced MTF with larger pupils. “This is especially helpful for nighttime vision needs,” Riaz said.

The enVista Aspire is based on the same platform and material as the previous enVista IOL, the MX60. This IOL has a posterior high-order aspheric surface to create a broader depth of focus. He explained that the optic of the IOL axis is an intermediate optimized zone with a blend zone between the central and peripheral power that provides a gradual transition of incoming light to minimize dysphotopsias. The net result is maintaining the excellent distance VA and improved intermediate vision with increased power of about 1.2 diopters (D) in the lens center.

Scenarios for using monofocal IOLs

Riaz described a patient who presented with decreased VA and complaints of debilitating photic phenomena. The patient had undergone cataract surgery elsewhere with a diffractive-optics trifocal lens (PanOptix, Clareon). The patient had previous myopic laser vision correction in the right eye and hyperopic laser vision correction in the left eye for monovision. The right and left eye VAs were, respectively, 20/40 and 20/50. The patient had bilateral high-angle alpha values of 0.7 and 0.6, respectively.

This patient also had an epiretinal membrane (ERM) in the right eye; Pentacam examination showed a topographic pattern consistent with myopic ablation in the right eye with a high-angle alpha value and in the left eye a hyperopic ablation pattern, with a respectable angle alpha but slightly larger total corneal higher-order aberration. These findings indicated the patient may not have been a good candidate for the diffractive IOL based on the unique corneal anatomy, visual angles, and ERM.

The best refractions achievable were 20/40 and 20/30, and the photic phenomena were particularly bothersome. Riaz suggested that with an IOL exchange using enhanced monofocal IOLs (enVista Aspire IOLs), the patient would not achieve complete spectacle independence for near reading; however, the intermediate and distance vision would improve by eliminating the photic phenomenon.

The ERM limited full correction, particularly in the right eye, with a VA of 20/30; the left eye VA was 20/25. The patient was refracted to 20/25 and 20/20, with minimal correction bilaterally. The IVA was also satisfactory, with a binocular uncorrected IVA of 20/30. The patient was particularly satisfied with the resolution of the photic phenomena.

The second case was a White man aged 69 years with Fuchs dystrophy and visually significant cataracts bilaterally. Given the patient’s corneal pathology, the patient was not a good candidate for diffractive-optics advanced-technology IOLs, but a monofocal plus IOL could improve the intermediate and near vision. He performed a cataract surgery combined with a Descemet membrane endothelial keratoplasty and implanted Eyhance IOLs bilaterally. The surgeries were performed 6 weeks apart; about 2 months after the second procedure, the uncorrected binocular VA was 20/30; minimal correction brought the right eye to 20/20 and the left to 20/25. The patient’s binocular uncorrected IVA was 20/25. The patient’s uncorrected near VA was 20/50 and very usable, primarily because he increased the font size on his electronic reading devices.

The third case was a man aged
59 years who presented for cataract surgery for a significant posterior subcapsular cataract and desired spectacle independence. The right and left VAs, respectively, were 20/40 and 20/25. The patient had against-the-rule astigmatism, 1 D in the right eye and 1.3 D in the left eye. The alpha angle values were 0.7 in the right eye and 0.5 in the left eye, which called into question the use of diffractive-optics IOLs.

For this highly motivated patient who wanted good intermediate and improved near vision, Riaz opted to implant a monofocal plus (enVista Aspire toric IOL ) in the right eye and an Apthera IOL (AcuFocus, Inc), an advanced technology lens with pinhole optics, in the left eye aiming for approximately –0.75 D, combined with a limbal relaxing incision to address the against-the-rule astigmatism.

About 1 month postoperatively, the patient had a good outcome. Uncorrected binocular vision was 20/20 at distance, intermediate 20/16, and near J1. This patient functioned extremely well with no photic phenomena.

“This is a case in which we can use an enhanced monofocal IOL in 1 eye and combine it with an advanced technology lens in the left eye and deliver this
patient a very similar outcome than what could be hoped to achieve using bilateral, diffractive-optics advanced technology lenses like a multifocal or trifocal lens and deliver a good outcome,” Riaz said.

The takeaway from these cases of patients who are not good candidates for diffractive-optics IOLs is that a monofocal plus IOL can be used and combined with an advanced technology lens that may be appropriate for that patient. In addition, a patient with 1 eye with a higher alpha angle and the other with an acceptable angle alpha can receive an enhanced monofocal IOL in the eye with the worse angle and a diffractive-optics advanced-technology lens in the eye with the good angle.

“This provides surgeons with some flexibility and creativity, and the patient can learn the different options available. Based on our discussions with patients, we can wisely choose lenses that are good options for patients in numerous, commonly encountered scenarios for today’s full-range cataract and anterior segment surgeon,” he commented.

Kamran M. Riaz, MD

E: Kamran-Riaz@dmei.org

Riaz is a clinical professor, Thelma Gaylord Endowed Chair in Ophthalmology, and vice chair for clinical research at the Dean McGee Eye Institute, University of Oklahoma, Oklahoma City.