Presbyopia-correcting IOL with nondiffractive design offers gains
Reviewed by Devesh Varma, MD
The model DFT015 IOL (AcrySof IQ Vivity Extended Vision; Alcon Laboratories, Inc), a new presbyopia-correcting intraocular lens (IOL), improved near and intermediate vision without negatively affecting the distance vision compared with an aspheric monofocal IOL (SN60WF; Alcon Laboratories, Inc) in 2 studies, according to Devesh Varma, MD, assistant professor in the Department of Ophthalmology and Vision Sciences at the University of Toronto in Ontario.
New mechanism of action
The study lens, Varma explained, has a new mechanism of action.
“The DFT015 IOL has a 2.2-mm zone, referred to as the wavefront-shaping X-Wave optic, incorporates 2 transition elements—1 is a slightly elevated smooth plateau that stretches (ie, delays) the wavefront, resulting in an extended focal range, and 2 is a small curvature change that shifts the wavefront, creating an extended negative focal range,” he said.
The 2 transition elements together result in a stretched and shifted wavefront.
“When the wavefront emerging from the posterior IOL collapses onto the retina, the effect is amplified,” Varma added. “When the wavefront reaches the retina, the focal range is extended, with a stretched light pattern.”
The benefit afforded by the IOL is the extended range of vision with a visual disturbance profile similar to that of the SN60WF IOL.
In addition, the DFT015 IOL is associated with almost no halos compared with a diffractive extended depth-of-focus IOL.
Two studies—one in the US and the other outside-the-US (OUS) trial in Australia, Canada, Spain, and the UK—were undertaken to evaluate the clinical outcomes of the DFT015 IOL and SN60WF IOL; the IOLs were each implanted bilaterally in the study patients.
In the US study, 106 and 113 eyes, respectively, received the DTF015 IOL and the SN60FW IOL; in the OUS study, the respective numbers of eyes were 154 and 119.
The primary outcome measures were the binocular defocus curve, binocular distance-corrected visual acuities (VAs) at all distances, and patient-reported visual disturbances.
The binocular defocus curves 6 months after implantation in both studies were similar.
“The DFT015 defocus curve was elongated with a flat peak and reached –1.5 to –2.0 D, providing about 20/32 correction,” Varma said. “The DFT015 provided similar distance vision and a superior range of vision in the intermediate range compared with the SN60WF IOL.”
Regarding the binocular distance-corrected VA at 6 months, in both studies, the DFT015 IOL provided distance-corrected intermediate VA and distance-corrected near VA that were approximately 1 line or better than those achieved with the SN60WF IOL.
The patients randomly assigned to either IOL reported they did not experience starbursts, halos, or glare 6 months after implantation. The results for both IOLs were similar.
The primary take-home message based on the results of the 2 studies is that the DFT015 with its nondiffractive design extends the range of vision, with improved intermediate and near vision compared with the SN60WF, without having a negative impact on distance vision.
In addition, the DFT015 has a visual disturbance profile similar to that of the SN60WF.
Devesh Varma, MD
E: [email protected]
This article was adapted from Varma’s presentation at the American Academy of Ophthalmology’s 2020 virtual annual meeting. He is a consultant for Alcon Laboratories, Inc, which funded the studies under discussion.