Take-home message: Surgeons share their lessons learned about new lens technologies for refractive cataract surgery, such as extended-depth-of-focus IOLs.
By Vanessa Caceres; Reviewed by Daniel H. Chang, MD, and Steven J. Dell, MD
Visual quality, depth of field, and night vision are three factors that come into play with premium IOL use—and each IOL choice may offer benefits with some of these factors but not others. Traditional presbyopia IOLs may increase depth of field, but they can decrease visual quality and nighttime vision.
With extended-depth-of-focus IOLs, there may be fewer sacrifices, said Daniel H. Chang, MD.
“Extended-depth-of-focus IOLs, which provide at least an additional 0.5 D of focus at 20/30, achieve a new set of compromises, and expand the options for surgeons to treat presbyopia,” said Dr. Chang, Empire Eyea and Laser Center, Bakersfield, CA.
This particular kind of IOL class appears to have fewer problems with glare and halos as well.
A paper published last year from the FDA and the American Academy of Ophthalmology took into account information from 200 stakeholders to try and pinpoint quality requirements for this type of IOL,1 Dr. Chang said.
The use of extended-depth-of-focus IOLs gives surgeons one more option for patients as they aim for better visual acuity in today’s patients, Dr. Chang said.
“Refractive cataract surgery addresses cataracts and refractive errors,” he said. “Not treating ametropia and presbyopia is not an option.”
Although patients may tolerate continued use of glasses, bifocal glasses have certain side effects, such as a greater risk of falls. Many patients may say they are comfortable using glasses without realizing they have a choice—such as extended-depth-of-focus lenses, he added.
This type of lens may cause a bit of starburst, but it does not have the problem with halos associated with some other IOLs, Dr. Chang explained.
Before extended-depth-of-focus IOLs even became available in the United States, the Tecnis Symfony IOL (Abbott Medical Optics)—approved in July 2016 by the FDA for use in United States, and previously approved in more than 50 countries around the world—was already challenging the definition of the category, Dr. Chang said.
“Extended-depth-of-focus lenses improve depth of field, have minimally decreased visual quality, and have reduced night vision symptoms compared with multifocal IOLs,” he said. “If an IOL can provide 1.0 D or more improvement in depth of focus and still maintain fewer side effects, it would approach the definition of a presbyopia-correcting IOL but have better acceptance than current-generation IOLs.”
On the other hand
Studies that asked patients with early-generation IOLs if they would pick the same IOL type again, 92% said “yes,” compared with 97% who have more modern IOLs, said Steven J. Dell, MD, medical director, Dell Laser Consultants, Austin, TX. The same percentage of people (97%) said they would choose to have the Symfony again, which Dr. Dell thought was an interesting comparison.
Dr. Dell was asked to address the drawbacks with extended-depth-of-focus IOLs, but he said he is actually excited about the technology.
Still, he raised the question of whether extended-depth-of-focus lenses really can create a non-zero sum game, where users do not have the typical visual gain or loss balanced by other gains or losses due to the lens type.
Some of the technology used in these types of lenses can be found in already existing approved technologies, Dr. Dell said.
For example, the small-aperture IC8 IOL (AcuFocus) is very similar to the Kamra corneal inlay (AcuFocus), he noted.
“You get a defocus curve, which you also shift in a myopic or hyperopic direction,” Dr. Dell said.
Lenses such as the AMO ZKB00 have excellent distance and intermediate vision, with 95% able to function comfortably, he explained.
“Extended-depth-of-focus lenses will change the way we approach patients, but we have some multifocal and accommodating IOL technology now that can almost reach the same level,” Dr. Dell said.
1. Lum F, Tarver ME, Kahook MY, et al. Special Commentary: Food and Drug Administration and American Academy of Ophthalmology Sponsored: Developing Novel End Points for Premium Intraocular Lenses Workshop. Ophthalmology
Daniel H. Chang, MD
E: [email protected]
This article was adapted from a debate at the 2015 meeting of the American Academy of Ophthalmology, in which Dr. Chang and Dr. Dell presented these perspectives on this topic. Dr. Chang indicated a financial relationship with Abbott Medical Optics, Allergan, Carl Zeiss Meditec, ClarVista Medical, Mynosys Cellular Devices, Omega Ophthalmics, and Rapid Pathogen Screening.
Steven J. Dell, MD
E: [email protected]
Dr. Dell indicated a financial relationship with Abbott Medical Optics, Advanced Tear Diagnostics, Allergan, Bausch + Lomb, Ocular Therapeutix, Optical Express, Presbyopia Therapies, and Tracey Technologies.