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Up Front | Sep 2008

Advanced IOLs Improve Surgery, Safety

Working with multifocal IOLs puts increased demands on the surgeon and staff; however, it results in surgical improvements.

Modern multifocal IOLs allow us to offer our patients a greater degree of spectacle independence than was possible in the past. Whether used in cataract surgery or refractive lens exchange (RLE), these IOLs provide crisp distance vision and functional near and intermediate vision for the great majority of patients.

Although multifocal IOLs offer numerous benefits, compared with monofocal IOLs they also place increased demands on the surgeon and staff. They call for a personalized approach to surgery, with new exams and more exacting measurements than ever before. Biometry and IOL power calculation must be precise to ensure on-target refractive correction. Eye dominance must be reliably determined, and pupillometry must be employed to select the proper multifocal technology for each eye. Additionally, patients pay a premium for these new-technology IOLs, so they are more demanding and, in many cases, more informed about their options than our standard cataract patients.

All these elements put a greater demand on the practice, requiring a meticulous step-by-step approach, more expenditure of resources, and more time spent with each patient; however, there is a definite upside to the increased effort. We have introduced new minimum quality benchmarks that have improved our results in all areas—in routine cataract surgery as well as RLE. We have reduced the number of surgical complications and improved patient-physician communication so that there are fewer misunderstandings and dissatisfied patients. Patients' needs have become the central focus of our efforts, and we make every effort to provide the type of postoperative vision each patient desires.

I have pushed my surgical technique to new limits—beyond what I had become used to in routine cataract surgery.

An important part of our effort to customize surgery to the patient's needs is selecting the appropriate IOL. We employ a custom-matching strategy, selecting the diffractive Tecnis Multifocal IOL or the zonal refractive ReZoom IOL (both manufactured by Advanced Medical Optics, Inc., Santa Ana, California) depending on patient characteristics.

In all cases, we begin by implanting the Tecnis Multifocal in the patient's nondominant eye. It is good to start with this IOL because it is relatively pupil independent and, with use of mydriatic drops, induces less perception of photic phenomena in the early postoperative period than the ReZoom.

In most cases, we wait approximately 1 week before implanting the ReZoom in the dominant eye. Exceptions to this are when the patient's pupil diameter in mesopic conditions is greater than 5.2 mm or if the patient complains of halos in the implanted eye. In these patients, and in those who seem to have equal dominance in both eyes, bilateral Tecnis Multifocal IOLs are used.

The reason we prefer to mix and match the Tecnis Multifocal with the ReZoom is that these IOLs are complementary. The ReZoom in the dominant eye provides crisp distance vision and good intermediate vision, and the Tecnis Multifocal in the nondominant eye provides excellent reading vision with relative pupil-size independence.

Leaving 1 week between procedures maximizes the benefit of multifocality, which is not achieved until both IOLs are implanted. In the week between surgeries, I assess the patient's visual results and satisfaction with the first eye and determine which IOL is the better choice for the second eye.

In a retrospective analysis of 60 patients (73% for cataract surgery, 27% for RLE) I implanted the combination of ReZoom/Tecnis Mulitfocal in 77% of eyes. The other eyes received bilateral Tecnis because of the 5.2-mm pupil size rule. The average age of the cataract patients was 74.2 years at the time of surgery, and the average age of RLE patients was 52.8 years.

In the Tecnis Mulitfocal eyes, mean UCVA at 6 months postoperative was 0.78 and mean BCVA was 0.92. In the ReZoom eyes at 6 months, mean UCVA was 0.84 and mean BCVA was 0.97 (Figure 1).

In a series of 55 eyes that underwent RLE, we measured spherical aberration with the WASCA Aberrometer (Carl Zeiss Meditec AG, Jena, Germany). In 15 eyes that received the ReZoom IOL, mean spherical aberration was -0.25 µm preoperatively and 0.13 µm at 6 months postop. In 40 eyes that received the Tecnis Mulitfocal IOL, mean spherical aberration was -0.42 µm preop and -0.02 µm at 6 months postop (Figure 2A). In the same group, total root mean square higher-order aberrations were 0.53 µm preop and 0.26 µm at 6 months postop in the ReZoom eyes, and 0.39 µm preop and 0.28 µm at 6 months postop in the Tecnis Mulitfocal eyes (Figure 2B).

To evaluate intermediate and near vision and reading speed, we acquired the Eyevispod Analysis System (PGB Srl., Milan, Italy). In an assessment of binocular uncorrected intermediate vision (60 cm; computer distance), in patients with custom-matched ReZoom and Tecnis IOLs, 84% were found to have efficient intermediate vision at 1 month postop and 88% at 6 months.

For uncorrected near vision, with monocular testing the Eyevispod device showed a mean result of J 5.0 in the Tecnis eyes and J 5.86 in ReZoom eyes at 6 months. With binocular testing, the same group demonstrated a mean of J 2.0.

This marked difference between monocular and binocular testing demonstrates the truth of the often-heard statement that multifocal IOL technology provides the best results with binocular implantation.

Here are some pearls and pointers we have learned from our recent experience regarding satisfying patients with multifocal IOLs in RLE:

  • Do not promise patients 100% spectacle independence;
  • Correctly identify the dominant eye;
  • Always use two methods for axial biometry: the IOLMaster (Carl Zeiss Meditec AG) and immersion A scan;
  • Measure pupil diameter in mesopic conditions and set a maximum of 5.2 mm for refractive multifocal implant (ie, ReZoom);
  • Start by implanting a diffractive technology (ie, Tecnis) in the nondominant eye;
  • Perform the second eye surgery within 1 week;
  • Tell the patient there is a learning curve for near distance reading, and offer the patient assistance during the curve with exercises on the Eyevispod device;
  • Perform Nd:YAG laser capsulotomy early;
  • Correction of residual refractive errors (within 0.75 D) can significantly reduce or eliminate glare and halos in specific situations (ie, night driving); and
  • Perform laser vision correction for residual refractive error after 4 months.

Because we now have improved diagnostic and surgical tools and techniques at our disposal, I predict that within 5 years this kind of personalized lens surgery will be widespread for both cataract surgery and RLE. Thus, the demands imposed on us by multifocal IOL technology will have helped us to improve lens replacement surgery across the board.

Matteo Piovella, MD, is Director of the Centro di Microchirurgia Ambulatoriale, Monza, Italy. Dr. Piovella states that he is a consultant to Advanced Medical Optics, Inc., and BD. He may be reached at tel: +39 039 389 498; e-mail: piovella@piovella.com.