The latest generation of multifocal IOLs provides patients with a tremendous opportunity for independence from spectacles. Compared with their predecessors, these lenses satisfy more patients and have fewer disadvantages. Concerns remain, however, including the potential for glare, halos, and night vision problems. In my experience, these symptoms are usually mild and temporary, but it is important to address dysphotopsia proactively when selecting and counseling patients. Moreover, I recommend being a perfectionist with regard to achieving emmetropia and mitigating any pre- or postoperative factors that could contribute to glare and halos. Finally, surgeons must understand how glare and halo data are collected and reported in order to judge their relevance to patients.
If surgeons make sure they hit their refractive target and optimize the corneal surface, their patients will generally be so pleased with their vision at distance and near that they will tell their friends. This positive word of mouth is a practice's best advertising.
SETING THE PATIENT UP FOR SUCCESS
Inquiring about a patient's hobbies and daily activities provides an important indication of his or her tolerance for nighttime dysphotopsia and facilitates the surgeon's recommendation of an IOL. Most of my patients' top priority when choosing a presbyopia-correcting IOL is spectacle-free near vision. For them, my lens of choice is the Tecnis Multifocal (Abbott Medical Optics, Inc.), because I find it provides reliable near vision as well as an excellent range of vision in different lighting conditions. For patients who are primarily concerned with performing tasks at an intermediate distance, however, I often recommend an accommodating lens. I am happy to implant the Crystalens (Bausch + Lomb) in these cases, but the patient must understand that he or she will not achieve the level of reading vision provided by a diffractive multifocal IOL.
Personality traits represent an important clue to a patient's ability to neuroadapt if he or she experiences significant dysphotopsia. In the past, I used surveys to gather this type of information, but I currently rely on my interview of patients and my staff's comments; no method is 100% accurate. When a “picky” patient asks me a lot of questions and expresses concern about glare and halos, I may advise him or her against choosing a multifocal IOL. Sometimes, taking the option off the table crystallizes for the patient that he or she is, in fact, willing to risk a small loss of contrast sensitivity or temporary glare in exchange for a broader range of vision without glasses. I find that these patients generally do very well with multifocal lenses.
In my experience, the biggest contributors to night vision problems after the implantation of a multifocal IOL are residual refractive error and dry eye disease (DED). Surgeons should address corneal astigmatism and perform postoperative enhancements as needed. Preoperatively, I obtain corneal topographies for every patient who will receive a presbyopia-correcting lens. If I detect any signs of ocular dryness, I pretreat the eye with artificial tears, punctal plugs, and/or topical cyclosporine to increase the accuracy of IOL power calculations and increase the patient's postoperative quality of vision.
I am a big proponent of postoperative nonsteroidal anti-inflammatory drugs to prevent cystoid macular edema, a complication that reduces the “wow” factor. In my experience, patients find the newer agents more comfortable to use. Because these medications can also be dosed less frequently (I prefer once a day), they are a relatively easy addition to the postoperative drug regimen. Currently, I have patients use bromfenac ophthalmic solution 0.09% (Bromday; Ista Pharmaceuticals, Inc.).
DIGGING INTO THE DATA
The available data on glare and halos can be confusing. Photic effects are tracked in all of the FDA clinical trials for multifocal IOLs, but the data are not necessarily gathered or analyzed in the same way across or even within different studies of a given IOL. The package insert for the Tecnis Multifocal 1-Piece IOL, for example, contains some surprising statistics. Thirty-seven percent of the multifocal group had moderate difficulty with halos, and 18% had severe difficulty at 1 year. Elsewhere in the same document, however, rates of 6% (moderate halos) and 5% (severe halos) are given.1 The latter numbers are more in line with my personal experience, but why are there two different reports? Minor changes in the way a question is posed can make results look very different.
As with any survey, it is easy to bias the responses, intentionally or not, through the phrasing of the question. When investigators asked a broad question (are you having any difficulties with your eyes or vision?), relatively few patients mentioned more than mild difficulty with glare, halos, or nighttime vision. In a third-party telephone survey that directly questioned patients about each symptom (how much difficulty do you have with halos at night?), the number of them reporting the problem was much higher. Curiously, the patients with monofocal lenses in the directed-question survey also reported high rates of photic phenomena, with 28% reporting moderate to severe difficulty with glare and 20% reporting moderate to severe difficulty with halos.1 Those rates do not match my experience at all. Plus, patients' overall satisfaction in the FDA trial was very high, with 92% saying they would choose a Tecnis Multifocal lens again.1 That finding, plus the high rate of difficulty in the monofocal group, tells me that “directed” responses may not accurately represent results.
In my practice, about 5% to 10% of patients who receive multifocal IOLs experience enough glare and halos to complain about them during the early postoperative period. After 1 year, however, those complaints largely disappear.
In terms of the nondirected responses in the Tecnis' package insert, the proportion of patients with severe photic phenomena (glare, starbursts, or halos) is 12% 4 to 6 months after the implantation of the Tecnis Multifocal IOL and 7% at 1 year. These statistics more closely match my clinical experience and are comparable to, or in some cases better than, what has been reported for other multifocal IOLs.2
Considering REAL-WORLD SYMPTOMS
In addition to developing a good understanding of clinical trial data, ophthalmologists should consider postapproval data, which better reflect how IOLs perform in the real world. The incidence of glare and halos is typically higher in FDA clinical trials, because participating surgeons may not be permitted to perform limbal relaxing incisions or enhancements or to make nomogram adjustments. DED also may not be addressed consistently.
In a recently published review of 76 eyes of 49 patients who were dissatisfied after receiving multifocal IOLs, photic phenomena were reported for 29 eyes (38.2%).3 The majority of these patients, referred to a tertiary care center, had received the AcrySof IQ Restor IOL +4.0 D (Alcon Laboratories, Inc.; 69 eyes), but others had a ReZoom IOL (Abbott Medical Optics, Inc.; one eye), Tecnis Multifocal lens (two eyes), or an AcrySof IQ Restor IOL +3.0 D lens (Alcon Laboratories, Inc.; four eyes). Most important is that almost all of the eyes had correctible factors beyond the multifocal design itself that might have contributed to the glare or halos. They included residual refractive error (35%), wavefront anomalies (21%), decentration of the IOL (17%), posterior capsular opacification (10%), and DED (4%). The investigators found that most causes of patients' dissatisfaction with multifocal IOLs can be treated successfully.
The aforementioned researchers' conclusion resonates with my own experience. By carefully selecting patients and using thoughtful surgical protocols, surgeons can minimize the incidence of dysphotopsia. Furthermore, effective counseling can help patients to prepare for potential night vision problems and to understand that these symptoms improve greatly within the first year. Overall, the value of multifocality for patients far exceeds the short-term dysphotopsia that a few experience with multifocal IOLs.
Douglas A. Katsev, MD, is in private practice at the Sansum Santa Barbara Medical Foundation in California. He is a consultant to Abbott Medical Optics Inc; Alcon Laboratories, Inc.; Allergan, Inc.; Bausch + Lomb; and Ista Pharmaceuticals, Inc. Dr. Katsev may be reached at (805) 681-8950; firstname.lastname@example.org.
- Tecnis Multifocal 1-Piece IOL, Model ZMB00 [package insert]. Santa Ana, CA: Abbott Medical Optics, Inc.; 2009.
- AcrySof IQ Restor [package insert]. Fort Worth, TX: Alcon Laboratories, Inc.; 2008.
- De Vries NE, Webers CAB, Touwslager WRH, et al. Dissatisfaction after implantation of multifocal intraocular lenses. J Cataract Refract Surg. 2011;37:859-865.