Surgeons weigh in: Accommodating vs. multifocal IOLs
Mitchell A. Jackson, MD, and Quentin B. Allen, MD, make their cases for the best IOL to correct presbyopia in cataract patients.
CEDARS Debates is a monthly feature in Ocular Surgery News. CEDARS — Cornea, External Disease, and Refractive Surgery Society — is a group of cornea, cataract and refractive surgery specialists, here to discuss some of the latest hot topics in ophthalmology.
This month, Mitchell A. Jackson, MD, and Quentin B. Allen, MD, discuss the pros and cons of using accommodating IOLs vs. multifocal IOLs for cataract surgery. There is an ever-growing interest in presbyopic correction after cataract surgery, and many patients expect to be spectacle free as much as possible after surgery. As patient expectations soar, so too does the need for an effective and reliable IOL to satisfy this demand. Both accommodating and multifocal IOLs have been in use for several years and have gained widespread acceptance. Surgeons continue to vary as to which IOL they prefer. Which IOL is truly superior, and how do these surgeons decide which IOL to select? We hope you enjoy this discussion.
Kenneth A. Beckman, MD, FACS
OSN CEDARS Debates Editor
Better accommodate your cataract patients’ high expectations
We are fortunate to have several options in the presbyopia-correcting IOL arena to offer our cataract patients. These fundamentally different lens designs give us an opportunity to tailor the implant to each patient’s needs and lifestyle, especially as we pursue the ideal of an emmetropic outcome. But being able to recommend the best choice for each patient also requires a thorough knowledge of the strengths and weaknesses of these lens technologies so that we can manage patients’ expectations appropriately. Having had extensive experience with both multifocal and accommodating lens designs, I have found that the latter provides the range and quality of vision that more of my patients hope to achieve after surgery, with fewer of the complaints commonly associated with multifocal IOLs.
There is only one U.S. Food and Drug Administration-approved accommodating IOL available to U.S. surgeons, the Crystalens Advanced Optics (AO) (Bausch + Lomb). Unlike multifocal designs, this lens is aberration-free and has uniform center-to-edge power, producing a more natural range of vision through physical accommodation in the eye (forward movement). The optic design also allows the lens to use 100% of available light regardless of pupil size or lens centration for enhanced contrast sensitivity.
I have implanted more than 2,000 of these lenses to date, and my experience with the Crystalens AO mirrors the results of clinical studies in which patients achieved superior intermediate vision and excellent distance vision immediately postop, with less neuroadaptation to the optics required than with multifocals. These studies also documented improved vision quality over time, with patients reporting better results 7 years after surgery than they did at 1 year.
While some patients may still require glasses to enhance near vision, I have found that those with active lifestyles will make the trade-off to get the quality of intermediate and distance vision the Crystalens AO provides. Most near vision tasks today involve laptops, iPads, tablets and smartphones, all of which can be seen clearly after Crystalens AO implantation. I am also confident that they will have minimal visual disturbance problems, such as glare or halos, associated with night driving and other routine activities.
In addition, unlike multifocals, the Crystalens AO can be implanted in patients with known corneal or retinal pathology without inducing any additional aberrations. There is no way to predict if someone may develop corneal and/or retinal pathology in the future; if he or she already has a multifocal IOL in place, it would be too late. In post-refractive surgery cataract patients especially, the AO optics of the Crystalens do not induce additional aberrations, such as the “waxy” vision issues reported with multifocals implanted in this setting. In my 2012 European Society of Cataract and Refractive Surgeons podium presentation in Milan, I showed that in patients with angle kappas greater than 0.4 mm (easily measured on devices such as the Marco OPD III or Tracey Technologies iTrace), those with multifocal IOL implants had much higher rates of visual complaints postoperatively. Since that study, I reserve my multifocal IOL use for patients who do limited night driving and have angle kappas of 0.4 mm or less.
The Crystalens platform was recently expanded with a toric design, the Trulign toric IOL. This lens represents another innovation because it is the first and only approved IOL for the simultaneous correction of astigmatism and a broader range of vision. Most toric IOLs only correct astigmatism, but this is the only one in the United States that can make the claim of improving uncorrected near, intermediate and distance vision (based on the FDA labeling). The Trulign shares the aberration-free and center-to-edge power advantages of the Crystalens and offers the surgeon effective centration and unparalleled rotational stability, with 96.1% of lenses displaying less than 5° rotation at 6 months postoperatively in the FDA study. In today’s refractive cataract surgery environment, hitting the “wow” factor for a patient on day 1 is more readily achievable with the Trulign if a patient has astigmatism and a cornea that cannot tolerate the placement of limbal relaxing incisions, for example.
Together, this family of unique IOLs allows me to correct presbyopia and/or astigmatism in my cataract patients without compromising vision quality. As with any premium IOL, careful patient selection and an open discussion about expectations and outcomes are critical to success with the Crystalens AO or Trulign. However, these lenses have become a cornerstone of my premium IOL practice.
References:Jackson MA. Effect of angle kappa on post-refractive surgery IOL calculations. Paper presented at: European Society of Cataract and Refractive Surgeons meeting; 2012; Milan.
Kandarel R, Colvard M. 7 year outcomes with the Crystalens At-45. Paper presented at: American Society of Cataract and Refractive Surgery meeting; 2013; San Francisco.
For more information:Mitchell A. Jackson, MD, can be reached at Jacksoneye, 300 N. Milwaukee Avenue, Suite L, Lake Villa, IL 60046; 847-356-0700; fax: 847-589-0609; email: email@example.com.
Disclosure: Jackson is on the speakers bureau for AMO and is a consultant for Bausch + Lomb.
Multifocal IOLs best overall presbyopic lens choice
With the advent of femtosecond laser for cataract surgery and the excitement over this new technology, the emphasis on presbyopia-correcting lens technology has taken a backseat to discussion of the merits and usage of new laser platforms. However, the decision on which presbyopic visual system patients elect to use for the rest of their life — monovision, multifocality, accommodating lenses or monofocal distance — is still the one that will affect their daily reality the most as they navigate their world each day. Therefore, the ideal presbyopic solution remains an important daily consideration for practicing cataract surgeons and their patients. I would firmly posit that multifocal IOLs remain the best overall choice for our patients who wish to both reduce the need for spectacle correction and avoid the scourge of surgical presbyopia correction.
Multifocal lenses allow our patients to maintain binocular visual summation at both distance and near, without sacrificing depth perception. The majority of patients implanted with a multifocal IOL enjoy excellent near acuity and do not need reading glasses for most situations. Patients implanted with an accommodating lens with a bilateral distance target will typically need a low-powered reading add. When a mini-monovision strategy is employed using accommodating lenses, binocular functional reading capacity is improved, while distance acuity and binocularity are sacrificed. In my experience, utilizing any monovision strategy increases the risk of needing laser vision enhancement, as the need for accurate refractive targeting in the distance eye leaves minimal room for error. With multifocal lenses, a mild refractive “miss” in one eye is usually well tolerated if the second eye has hit the refractive target. This does not hold true with monovision.
Accommodating lenses have an inherent shortcoming in predicting effective lens position due to the haptic design. The lens optic may be slightly more posterior or anterior than anticipated due to capsular size issues. In my experience, refractive predictability with accommodating lens has been less consistent than with monofocal or multifocal lenses. This is also one reason some surgeons advocate placing a capsular tension ring when using accommodating IOLs to expand the capsular fornix, as well as to delay or prevent capsular contraction.
Capsular contraction in a monofocal IOL usually does not significantly alter the position of the optic. However, even in a monofocal IOL, some postoperative optic movement can occur, either anteriorly or posteriorly, especially if zonular compromise is present. These forces may have even more impact on an accommodating lens, and early YAG laser may be useful in addressing these concerns.
Due to these considerations, use of accommodating lenses involves careful surgical planning, evaluation of zonular and capsular status, and meticulous cleaning of the anterior capsular epithelium to reduce postoperative capsular fibrosis and contraction.
The desire for spectacle independence remains the main reason that patients inquire about presbyopia correction. I presented a study in 2011 at the American Society of Cataract and Refractive Surgery meeting that evaluated spectacle dependence and patient satisfaction among patients implanted with multifocal lenses and those with accommodating and monovision strategies. The group with the highest spectacle independence rate was the multifocal lens group. Patient satisfaction was much higher in the multifocal lens group compared with the accommodating lens group, as well. This result confirmed what my anecdotal experience had been.
Based on these considerations, my “go-to” lens for presbyopia correction is a multifocal lens. Of course, based on patient needs, amount of night driving, personality type, anatomy considerations such as pupil size and other factors, I will choose which type of multifocal and, in some patients, even implant an accommodating lens. I believe that there is a place for each of these technologies, and we as surgeons are fortunate to have options to customize for each patient.
For more information:Quentin B. Allen, MD, can be reached at Florida Vision Institute, 1050 SE Monterey Road, Suite 104, Stuart, FL 34994; email: firstname.lastname@example.org.
Disclosure: Allen is a consultant and/or on the speakers bureau for Alcon, Bausch + Lomb and Allergan.