Eyeworld

68 | EYEWORLD | APRIL 2019 ATARACT C by Chiles Aedam R. Samaniego EyeWorld Contributing Writer Contact information Chang: dchang@empireeyeandlaser.com Loden: lodenmd@lodenvision.com Wong: shannon@austineye.com Yeu: eyeulin@gmail.com "T he U.S. FDA has defined an EDOF [extended depth of focus] IOL as a lens that provides at least an additional 0.5 D of 20/30 acuity range over the baseline lens mod- el," Daniel Chang, MD, told EyeWorld. "Additionally, the clinical defocus curve should decrease strictly monotonically (without an inflection upward)." In other words, as the alternate nomenclature for this type of lens suggests, EDOF IOLs pro- vide an extended range of vision as opposed to a number of peaks or focal points of acuity. EyeWorld reached out to Dr. Chang as well as James Loden, MD, Shannon Wong, MD, and Elizabeth Yeu, MD, to get some clarity on a range of topics concerning this new generation of IOL. Expanding the point Currently, the Tecnis Symfony (Johnson & John- son Vision) is the only FDA-approved EDOF IOL. This IOL uses a diffractive optic that employs a proprietary echelette design. In addi- tion to extending the depth of focus, the design manipulates chromatic aberration, according to Dr. Loden. Other technologies are being employed to achieve EDOF. The IC-8 (AcuFocus), approved for an investigational device exemption by the FDA in November 2018, uses pinhole optics, while others, Dr. Chang said, "attempt to leverage aberrations" to achieve the same effect. The difference between EDOF and multi- focals is pointed. Multifocals currently come in bifocal and trifocal designs, the latter only avail- able outside the U.S. "These IOLs provide two to three areas of more focused light along the defocus curve," Dr. Yeu said. In other words, Dr. Wong said, EDOF IOLs provide continuous clear focus over an extended range while multifocals involve relatively defo- cused areas between focal points. Thus, using multifocals involves nailing the refractive outcome to get two smaller focal points into usable ranges. In contrast, "EDOF IOLs have a single larger focal range with greater flexi- bility for refractive outcome," Dr. Chang said. To the patient, the difference should be clear. "The Symfony IOL allows for ~92% light trans- mission, which is greater than what is seen with domestically available multifocal IOLs," Dr. Yeu said. "Clinically, this translates to greater contrast sensitivity." In addition, in Dr. Loden's experience, EDOF IOLs have fewer halos and dysphotopsias than multifocals, albeit with the trade-off of less uncorrected fine near vision without spectacles. EDOFs vs. multifocals in practice EDOF IOLs have limitations, so a role for the traditional multifocal remains. "In my market the prime candidates for EDOF technology lenses are patients who are distance and intermediate dominant," Dr. Loden said. Prime candidates for EDOF IOLs in his practice include farmers who spend the day op- erating heavy equipment guided by GPS displays positioned about 3 feet away from their eyes or otherwise outdoor-oriented patients. In contrast, multifocal candidates say they love reading, love cooking, and hardly drive at night. Meanwhile, Dr. Chang uses the Tecnis Sym- fony EDOF IOL as his go-to presbyopia-correct- ing IOL "because of its superior image quality, continuous range of vision, night vision symptom profile, and availability in a toric format," he said. However, "if patients want better uncorrected EDOF fundamentals What they are, how and when to use them EDOF IOL defocus curve; brown = Symfony ZXR00 (n=62); red = monofocal ZCB00 (n=73) Source: Daniel Chang, MD About the doctors Daniel Chang, MD Cataract and refractive surgeon Empire Eye & Laser Center Bakersfield, California James Loden, MD Founder and president Loden iVision Centers Nashville, Tennessee Shannon Wong, MD Austin Eye Austin, Texas Elizabeth Yeu, MD Assistant professor of ophthalmology Eastern Virginia Medical School Partner, Virginia Eye Consultants Norfolk, Virginia Financial interests Chang: AcuFocus, Johnson & Johnson Vision Loden: Johnson & Johnson Vision Wong: Johnson & Johnson Vision Yeu: Alcon, Carl Zeiss Meditec, Johnson & Johnson Vision

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