Two accommodating IOLs — the AT-45 (Crystalens; Eyeonics, Aliso Viejo, Calif) and the Akkommodative 1 CU (Human Optics, Erlangen, Germany) — are available today. Although many surgeons report satisfying-to-excellent results with both lenses, thorough clinical studies revealed only limited accommodative power, which is insufficient to achieve spectacle independence in most patients.1-4 Therefore, particularly in Germany, the majority of cataract surgeons did not use these IOLs in their practice. New accommodating IOL concepts (eg, the dual-optic Synchrony [Visiogen, Irvine, Calif]) are promising, however, are still under clinical investigation.
Implantation of a multifocal IOL is the second approach to achieve spectacle independence in our patients. Over more than 10 years, the only multifocal IOL implanted in a large number of eyes was the Array IOL (Advanced Medical Optics, Santa Ana, Calif). This lens was restricted by some drawbacks (ie, limited near vision; reduced contrast vision, particularly under mesopic lighting conditions; and photic phenomena including halos and glare).
In contrast to the five refractive optical zones of the Array, the diffractive optic design of the 811E multifocal IOL (Pharmacia, Uppsala, Sweden) performed better.5 The lens, however, has a disadvantageous rigid PMMA material and therefore needs a large incision. This prevented the use of this IOL in a greater number of patients.
Several newly developed multifocal IOLs with improved optical concepts were investigated in clinical studies and are now on the market (eg, Tecnis MF [Advanced Medical Optics], the Restor [Alcon Laboratories, Fort Worth, Texas] and the AcriLISA [Acritec GmbH, Hennigsdorf, Germany]). All of these multifocal IOLs use a diffractive optic design.
Editors note: According to the company, LISA is an acronym for light intensity distribution; independent from pupil size; smooth refractive/diffractive surface profile; and aberration corrected.
With application of a diffractive or combined refractive-diffractive optic, the visual performance of these new multifocal IOLs became independent of the pupil size, which was one significant drawback of the Array. The apodized design of the Restor lens even results in an improved distance vision with increasing pupil size.
The introduction of an aspheric lens design is one major advancement in image quality, and it has been proven to increase contrast sensitivity in monofocal lenses.6 Two of the new multifocal IOLs (ie, the Tecnis MF and AcriLISA) are aspheric lenses.
My colleagues and I performed clinical studies with the Tecnis MF and AcriLISA lenses, which are currently submitted for publication. A Restor study is currently under way, and therefore my report reflects results with the Tecnis MF and AcriLISA only. We compared the Tecnis MF to the Array in 50 patients (100 eyes). Uncorrected and distance corrected near visual acuity with the Tecnis MF were significantly better than with the Array (P<.001) (Figure 1), as was mesopic contrast sensitivity at high spatial frequencies. Patients also experienced greater spectacle independence with the Tecnis lens (82.6% vs 33.3%), resulting in a very high level of patient satisfaction.
The AcriLISA has an unequal light distribution (ie, 65% for distance vision and 35% for near vision). This concept is based on (1) the consideration that most patients prioritize distance vision and (2) that 35% of light is sufficient for reading quality under normal lighting conditions. Another aim of the AcriLISA system is to reduce the well-known side effects associated with multifocal IOLs, particularly halos, by producing one dominant and one weaker image. Furthermore, smooth steps between the diffractive zones were engineered to reduce glare. Our investigations showed excellent distance visual acuity and good near vision under photopic lighting conditions with significantly better results tested binocularly (Figure 2).
Intermediate visual acuity was also good, as the pseudoaccommodation range was 5.50 D (Figure 3). Eighty percent of patients (n=20 patients, 40 eyes) reported halos, however, they were without significant impairment. Only 10% of these patients used spectacles.
Our results with the Tecnis MF and AcriLISA, two of the new multifocal IOL generation lenses, demonstrated significant improvements in visual function, spectacle independence, and patient satisfaction compared with previous models. Some reduction of contrast sensitivity and the persistence of photic phenomena remain when compared with monofocal IOLs, but there is less subjective impairment.
We should explain to our patients that the improvement of visual function will occur, however, not directly after surgery — probably due to adaptation of the perception of two images. Our investigation showed an increase of visual acuity, even between 3 and 6 months after surgery (Figure 4).
Patient selection is crucial. Excluding patients with high demand for contrast vision, we achieved a high patient satisfaction with these new multifocal IOLs. Therefore, in patients who want to be independent from spectacles, I prefer multifocal IOLs instead of accommodating lenses due to their uncertain and insufficient efficacy.
Ulrich Mester, MD, is medical director of the department of ophthalmology, at Bundesknappschaft's Hospital, in Sulzbach, Germany. Professor Mester did not provide financial disclosure information. He may be reached at sek-augen@kksulzbach.de.
I use the Crystalens in patients who desire near and intermediate vision and clarity of distance vision.
By Stephen G. Slade, MD, FACS
In today's cataract and refractive market, accommodating and multifocal IOLs are both innovative and useful technologies for the treatment of presbyopia. Currently, I use all of the refractive lenses that are available in the United States. Prior to the US Food and Drug Administration (FDA) approval of the Crystalens (Eyeonics, Aliso Viejo, Calif) accommodating IOL, I was involved with the early developmental stages of this technology. I performed the first Crystalens implantations in North America, served as the medical monitor for the FDA study and presented the related data to the FDA panel. I have also been using the Acrysof Restor (Alcon Laboratories, Fort Worth, Texas) and the Rezoom (Advanced Medical Optics, Santa Ana, Calif) since each multifocal IOL was approved. As they differ in function and have various strengths and weaknesses, all three lenses are useful to me and my colleagues.
The accepted treatment goals for accommodating lenses include three indications: (1) the correction or significant improvement of presbyopia; (2) the correction of high degrees of nearsightedness or farsightedness; and (3) the restoration of clear vision following cataract extraction. As surgeons, we must juggle all three indications on a case-by-case basis to find the right lens. For example, a patient may have a high degree of nearsightedness or farsightedness but less of a cataract. Conversely, if the patient has a high significant cataract it does not matter if he/she is nearsighted or farsighted, the cataract would have to be removed in any instance to restore vision and help correct presbyopia. A younger noncataractous individual would not necessarily receive one of these IOLs. Instead, the surgeon would likely perform LASIK or implant an ICL.
PROS AND CONS OF ACCOMMODATIng IOLS
Accommodating IOLs are not as dependent on pupil size for focus as their multifocal counterparts. In an accommodating IOL, the entire lens focuses 100% of the light back to the retina. With multifocal IOLs, the light is split and focused at different points due to the concentric zones.
The implantation of the Crystalens is straightforward and it is one of the fastest lenses to implant. The surgery does require need a watertight wound, meticulous cortical clean-up and a precise capsulorhexis, but these are advantages for any cataract surgery.
In some patients, multifocals may provide better near vision. For instance, a patient with only one eye implanted with a Crystalens may not have the same rate of acheiving J1 as another patient with one eye implanted with a multifocal. When you look at binocular vision in patients implanted binocularly, however, the patients may be similar in their abilities to read up close. This is achieved by providing a bit of monovision in the nondominant eye of the patient with the Crystalens. In fact, according to the FDA clinical trials, a high percentage of patients implanted bilaterally with Crystalens (73.5%) did not need glasses for daily activities. Typically, these results are rapid and actually improve over time.
OVERALL PREFERENCE
The positive feedback from patients who have received the Crystalens has been high. At our practice, we use the Acrysof Restor, the Rezoom, and the Crystalens, and the majority of the feedback has been encouraging. Our patients who report the smallest amount of negative feedback regarding overall vision, though, have been those who received the Crystalens. In our experience, more patients complain about glare and halos with multifocals than with the Crystalens. Results from FDA trials demonstrated similar findings concerning the increased inducement of glare and halos with multifocals as well.
PATIENT SELECTION
When considering which IOL to implant in a particular individual, careful patient selection is key to achieving successful postoperative results. In general, if the patient needs good J1 near vision, my colleagues and I lean toward implanting the Acrysof Restor. If there has been a rupture in the posterior capsule or a tear in the anterior capsule, or if there is zonular weakness, a multifocal may, again, be a better option. Additionally, the multifocals are the only choice for sulcus implantation. If it is a patient who needs more of a bifocal effect, we look at multifocals.
We choose the Crystalens for patients who desire more intermediate vision and the clarity of the distance vision. The Crystalens offers excellent quality of vision and is often our choice for more active patients. Intermediate vision is important to most patients today considering the high levels of cell phone, computer and PDA usage.
Not only does patient selection play a role, but it is necessary to perform careful individual eye assessments. In certain cases, it may be appropriate to mix accommodating and multifocal IOLs in order to achieve the optimal result. In contrast, a monofocal lens remains the best solution for some patients.
FUTURE MODIFICATIONS
Presently, trials are being conducted for several newer generation accommodative lenses, such as the Akkommodative 1CU (Human Optics, Erlangen, Germany), with reportedly favorable preliminary results. Additionally, Eyeonics is working on various improvements that it will plan to integrate into its Crystalens technology, with the aim of increasing accommodation and further improving the quality of near vision. With these advancements, accommodating lenses will surely be an option for many surgeons and patients.
Stephen G. Slade, MD, FACS, is in private practice in Houston. He states that he has consulted for Eyeonics. Dr. Slade may be reached at sgs@visiontexas.com or +1 713 626-5544.
