Eyeworld

EW FEATURE 47 JCRS study renews discussion on lens preference E ver since Nov. 29, 1949, when Sir Harold Ridley, M.D., F.R.S., first success- fully implanted an IOL in a patient in a London hospital, surgeons have researched, debated, and sometimes obsessed over the best surgical lens to use. Nearly 62 years later and after many advances in the surgical tech- nique and the lenses themselves, the discussion continues—this time over multifocal versus monofocal IOL im- plants for presbyopia correction. While monofocal IOLs are still considered the standard, especially in distance vision, advocates for the latest in multifocal implants say that patients' push for spectacle inde- pendence make multifocals a more attractive choice. An exciting study led by Fuxiang Zhang, M.D., in the March issue of the Journal of Cataract and Refractive Surgery did a head-to-head comparison of the technologies, with both continuing to show great promise. JCRS study In the study, researchers set out to compare how patients with bilateral diffractive multifocal IOLs stacked up against those who were im- planted with monofocal IOL mono- vision. Forty-three patients received ei- ther the AcrySof ReSTOR SN60D3 multifocal IOL (Alcon, Fort Worth, Texas) or the monofocal AcrySof SN60WF IOL (Alcon) as monovision. At the 3-month mark, investigators found that the multifocal IOL group did slightly better in terms of bilat- eral uncorrected distance and near vision, but the difference was not statistically significant. The monovi- sion group experienced better inter- mediate vision, which allowed them to use computers with significantly less difficulty than their multifocal counterparts. Monovision scored higher in terms of satisfaction, fewer complaints, and less out-of-pocket costs. The pseudophakic monovision patients achieved comparable dis- tance and near vision, but without the risk of disturbing visual symp- toms sometimes associated with multifocal IOLs. Multifocal options James A. Davison, M.D., Marshall- town, Iowa, said multifocal and monofocal lenses represent strategies to improve spectacle-free real world vision performance, but both come with their own set of optical com- promises. Dr. Davison said he prefers mul- tifocal lenses because they are "high-performance" devices, which provide simultaneous bilateral fine stereoscopic vision. He mostly uses ReSTOR lenses and said the latest lens would have fared better in Dr. Zhang's JCRS article. "The problem with the article is that it used the first generation ReSTOR lens," Dr. Davison said. "The more modern generation lens would have an expectation to over- come some of the results that were mentioned in the [JCRS] article. It has an aspheric surface, which will help with contrast sensitivity." The newer lens is better for "quality of vision, fewer halos, less glare, and improved computer dis- tance near performance," he said. "Achieving a plano result is our biggest challenge because of the cu- mulative effect of the contributions of all the various error sources," Dr. Davison continued. "These include measurements of axial length, ker- atometry, anterior chamber depth, lens thickness, and formula applica- tion and computations for each in- dividual patient, and then having to pick between IOLs that only come in 0.5 D increments." Dwayne K. Logan, M.D., At- lantis Eyecare, California, said he prefers the Tecnis multifocal IOL (Abbott Medical Optics, AMO, Santa Ana, Calif.) because, in his opinion, it offers excellent distance and near vision, as well as intermediate vision comparable to other multifocal lens options. Because the diffractive rings on the Tecnis lens extend out to the pe- riphery of the lens, patients are able to see better in dimmer light, Dr. Logan said. "With a lot of my patients, when I am recommending these pre- mium lenses for multifocality, I'm selling the fact that patients are going to be able to see at distance and near in all levels of light," Dr. Logan said. Although he will use other mul- tifocal lenses when needed, Dr. Logan said it benefits his patients for him to stick with his favorite pre- mium lens. "I have a very high conversion rate because I've found what I'm selling and that's what I sell. I'm not all over the place," he said. There are drawbacks, however, including some dysphotopsia. "I tell patients that with this lens they're going to lose some con- trast sensitivity, but the nature of the lens is such that if we have all of our parameters corrected, the vision will be relatively comparable," he said. "They may lose one line of vi- sion, but the brain would not know the difference if we eliminate all of the other variables." The multifocal lens is better for patients who want to achieve total spectacle independence, Dr. Logan said. To that end, ophthalmologists should maintain a "brilliant" rela- tionship with the patient's primary care physician, as well as make sure that refractive errors are corrected "in order for patients to really enjoy these lenses." The face of an ideal multifocal patient is shifting from younger, ac- tive patients to anyone who might appreciate spectacle independence, Dr. Logan said. "I used to say that they were for patients who are still working and are young, enthusiastic, and moti- vated, but I have patients who are 80-90 years old and they enjoy these lenses as well," he said. "They enjoy not having to wear glasses, and it makes them more active. They're out and about, and it's almost like it turns back the clock a little." Multifocals are contraindicated in patients who have any type of maculopathy, corneal disease, or opacification of the cornea. They would not do well in patients who have conditions that might affect the transmission or processing of light back to the brain—for example, a stroke, some type of atrophy from glaucoma, or a type of genetic disor- der that affected the retina, optic nerve, or the brain, Dr. Logan said. "That is why we have to have a bril- liant relationship with the primary care doctor, so that we know what the patient's medical condition is." Dr. Logan said the utilization of multifocal lenses is low because sur- geons don't believe that they can achieve as good vision as with the monofocal approach. "The whole goal now is to have doctors educate their patients on the fact that lens technology has im- proved significantly, to the point where we're getting results compara- ble to monofocal lenses. That wasn't the case with the first generation of these lenses," he said. Focusing on monovision For his part, Graham D. Barrett, F.R.A.N.Z.C.O., clinical professor, Lions Eye Institute, Perth, Australia, and Sir Charles Gairdner Hospital, Perth, said he has several reasons for preferring monovision. First and foremost, it offers the option of reversal. "At any time, patients can put on their spectacles and get full binocular vision with no compro- mise," Prof. Barrett said. Vision can be adjusted with a refractive proce- dure such as LASIK, he added. "If you have an unhappy multi- focal patient, explantation is some- times required because there's no way you can correct multifocal vi- sion," Prof. Barrett said. Vision with monofocal lenses is more robust, and the procedure is easier to explain to patients, he said. "Monovision will tolerate astig- matic defocus much better than a multifocal lens," he said. As for the patients, "Monovision is something patients can easily comprehend. You can demonstrate the type of vision they're going to get. It makes the whole exchange easier and faster." February 2011 June 2011 PRESBYOPIA by Jena Passut EyeWorld Staff Writer The great debate: Monofocal vs. multifocal AT A GLANCE • Experts share preferences on two types of lenses • Monofocal patients fared slightly better in the JCRS review, while multifocals did negligibly better at distance and near • Neither lens is ideal for patients with maculopathies continued on page 48

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