When presbyopic lenses such as ReSTOR and ReZoom were first approved, people didn't know exactly what to expect from them in their daily surgical practice. Some surgeons may have overestimated the benefits they'd confer to presbyopes, while others may have had a dimmer view of their usefulness. The truth, as always, was somewhere in between. Now, a couple of years later, surgeons are much more experienced in these implants, and know how to maximize their advantages while minimizing their disadvantages with the right patients. Here's what several experts think about the devices they use and a look at the characteristics of the newest entrant in the field, the Tecnis multifocal lens.

The Best Lens for the Job

Armed with a knowledge of the different presbyopic lenses, surgeons can tailor a lens to a particular patient.

"I think all of the lenses have roles in various patients," says Minneapolis surgeon Elizabeth Davis. "If I have a patient who's interested in presbyopic correction and he feels he'd be intolerant of glare or halos—so quality of vision is paramount—and he wouldn't mind using reading glasses occasionally for small print and wants good distance and intermediate visual acuity, I'd use the Crystalens. In such a case, I bring up the fact they he may not be totally free of reading glasses postop so he understands that." Dr. Davis estimates that half of her Crystalens patients get away with not using glasses, while the others need a pair of readers. "For patients whose biggest goal is to eliminate glasses altogether, that's when I consider multifocal or diffractive lenses," Dr. Davis adds.

Sarasota, Fla., surgeon William Lahners has two options for presbyopic lens implantation, and he bases the final choice on the patient presentation. "The first is for a patient with normal-sized pupils that aren't excessively large or small, and for someone who doesn't have a vocation such as an airline pilot, truck driver or the like," he explains. "For this patient, our approach is to put a ReZoom lens in the dominant eye and then, about a week later, reassess that eye and determine the lens selection for the non-dominant eye. Usually, after receiving the ReZoom in the first eye, they'll say their distance vision is fabulous and that they haven't seen that well in as long as they can remember. However, they'll say the near vision is good, but they wish they had some more power in the other eye. If they say anything like that, they'll get a ReSTOR or diffractive lens in the non-dominant eye." He estimates he has to do this in about 70 percent of the presbyopic lens patients. Dr. Lahners says he's seen a benefit in including the patient in the process like this. "The big advantage of incorporating the patients in this custom match type of approach is that they tend to adapt to the lens better and also give you better feedback," he explains.

Dr. Lahners' second approach is for pilots, professional drivers or patients with very small or very large pupils. "For these patients, we use the Crystalens HD in the dominant eye, then reassess the non-dominant eye and induce a little bit of monovision with another Crystalens HD or use a diffractive lens like a ReSTOR," he says. "I do this because though the ReZoom is a good lifestyle lens, if the patient has small pupils he's not going to get the middle-vision zone of the lens. So, in a 2- or 2.5-mm pupil, all you're really giving someone is an expensive monofocal distance lens. However, someone with very small pupils will do well with the Crystalens HD because he's also going to benefit from that diffractive element of having a small pupil.

"In people with large pupils, the opposite is true," Dr. Lahners adds. "If they have traumatic mydriasis or are very young, they may get excessive halos from the outer bands of the ReZoom lens. That would also be an argument for Crystalens HD in these patients. The same goes for pilots. Though I've implanted all of the types of multifocal lenses in pilots, if a pilot has to have a Class 1 medical qualification, which means 20/20 acuity in both eyes, it would probably be easier for him to qualify with a single-vision lens, and we'd use the accommodative lens in such a patient. If I use a mini [0.75 D in the non-dominant eye] monovision in this patient, he'll still need glasses to fly. If he doesn't want glasses to fly, I'll target both eyes for emmetropia and caution him that he'll most likely still need to wear some reading glasses depending on the light and what he's trying to read."

Surgeons say they feel the Crystalens HD is yielding better near vision than its predecessors, thanks to a modification of the center of the optic. "There's a 1.5-mm diameter bump in the center," explains Indianapolis surgeon Kevin Waltz. "It's elevated by just a couple of microns. It's not enough to give a second image, but enough to give a slight increase in the central power. So, when the pupil constricts, the power of the lens is changed to slight myopia."

Dr. Waltz will also mix lens types if he thinks it will benefit the patient. "I'm a believer that mixing and matching makes a lot of sense in most patients," he says. "None of these lenses is perfect, so if you can get a combination of effects, that seems to work better. You have to prepare the patient for the reality that the vision will be different, but it's no different than monovision. If you put an accommodating lens in one eye and a diffractive in the other, it works very well, because whatever symptoms you get from the diffractive can be suppressed by the accommodating lens and wherever you don't get strong reading vision from the accommodative lens you can get it from the diffractive. So, my default combination is an accommodative lens in one eye and a diffractive in the other."

Though surgeons say explants are inevitable with any of the lenses, there are steps you can do to minimize them.

"It depends a little bit on how aggressive you are in actually putting them in," says Dr. Waltz. "If you're conservative in whom you choose, you almost never have to take one out. My explantation rate is a lot less than one in 100. But if you get a little more aggressive, you might have to take one out. By conservative I mean you never put one in a myope, and always put it in a hyperope that's +2 D or more. These are the easiest people to make happy. The next group is the high myopes, while the people who are emmetropic or slightly myopic are very difficult to make happy."

The ReSTOR +3 D Arrives

Alcon recently received U.S. Food and Drug Administration approval for a version of its ReSTOR lens with a 3-D add, a little less than the original 4-D ReSTOR. The lens was scheduled to ship to surgeons in mid-January, and physicians are still determining how it may best be put to use in their practices. "The 3-D add moves the working distance away from the patient," says Dr. Waltz. "With the 4-D add, patients would complain that the working distance was a little bit close. The problem is, if the patient is even a little bit hyperopic with the 3-D ReSTOR, the working distance is going to be 60 cm or 70 cm or more away, and that's going to be a problem. So, one of the things we'll have to remember is, with the 4-D ReSTOR, you want to hit plano or slightly hyperopic. But, with the new 3-D ReSTOR you want to hit plano or a little myopic. This isn't a major change but an important inflection, because we only get lenses in 0.5-D increments. So, you have to be careful about how you shade it, because you're not going to have exactly the lens you want sometimes."

Marshalltown, Iowa, surgeon James Davison wonders if it might be useful to mix the two types of ReSTOR lenses. "I think the 3-D will put the working distance at a more reasonable range for people and, hopefully, improve their performance," he says. "I don't know, though, if we're going to use the old ReSTOR and the new ReSTOR for bilateral implantation, which might give the best of both worlds. If you took the average, younger cataract-age person, like 50 or 60, maybe the new ReSTOR would be better for both eyes. If you take someone, say, 65 to 70, you could kind of mix them. And, for an older person, the 4-D ReSTOR might be better."

Though the new ReSTOR isn't in widespread use just yet, there is some speculation that it may cause more dysphotopsias than the 4-D version. "The 3 D will have a few more adverse symptomatologies than the 4 D, because the 3 D has less distance between the distant and near images, while the 4 D splits them farther apart," says Dr. Waltz. Some, however, think this remains to be seen. "I haven't seen any data that suggest that's occurring," says Dr. Lahners. "And from the information I've received from the company, that doesn't sound like it's been an issue on the test bench. But I think we'll know more when we see and use the lens. That's always the ultimate test: seeing the lens in action and actually working with patients who have the lens. That's what drives clinicians."

The Tecnis Multifocal

AMO's Tecnis multifocal intraocular lens received FDA approval just last month, so it's worth a look in terms of how it might fit into your practice. Here is a discussion of the lens and the results of the patient study, which compared the results of 121 Tecnis patients to those of 122 monofocal lens recipients. At one year, 114 multifocal patients were available for follow-up.

The Tecnis has an aspheric anterior surface and a full diffractive posterior surface. It's available in both silicone (with a square edge) and acrylic (with the OptiEdge) versions. The optical add is 4 D.

In the FDA study, patients were able to read 20/30 print size at 148 words per minute vs. a control group of monofocal patients who could read 20/63 print at 117 words per minute, a difference that was statistically significant. Ninety-three percent of the Tecnis MF patients could see 20/25 or better at distance and 20/32 or better at near with distance correction. One patient (0.8 percent) required pupilloplasty and bilateral lens explantation due to halos and glare; three (2.4 percent) needed lens exchange to correct the power and one (0.8 percent) had an exchange because he'd received the wrong type of lens.

"The unique property of the aspheric Tecnis lens is that it's a full-optic diffractive lens," explains Dr. Waltz, who presented Tecnis MF data at the most recent American Academy of Ophthalmology meeting. "This means that you get a strong distant and near image regardless of pupil size. The only time the full-optic diffractive lens is a disadvantage is if you've got a large pupil and you're driving at night. You can reasonably expect to get more dysphotopsias in that situation. Still, though you give up a little bit in that environment, when you actually get to the restaurant you'll be able to read the menu without glasses." Dr. Lahners feels similarly, saying, "In my experience, one of the challenges of the ReSTOR is that reading vision tends to be dependent on having a lot of bright light, so what you're doing is driving the pupils down so you're using the central 3.6-mm diffractive portion of the lens. But with the Tecnis multifocal, if a patient is in a lighting condition that only supports a 4-mm pupil, he'll still have the multifocal power of the lens to read, so he'll be able to read in lower light. But, you never get something for nothing with optics, and because the Tecnis MF is a full diffractive optic, it makes sense that there may be more issues with night driving and potential rings around lights at night, because then the pupil will be larger."

Though new technologies will arrive and change the state of lenses, for now surgeons say they can successfully use the devices they have in the right patients. "As much as everyone likes to say that multifocal lenses are on their way out, I have to say the best results we've achieved to this day are with multifocal platforms and some of our happiest patients are multifocal patients," says Dr. Lahners. "I think they're here to stay until we have a lens that corrects distance and provides an accommodative amplitude that's similar to a natural lens."

Dr. Davis is a consultant for Bausch & Lomb. Dr. Lahners consults for AMO, Alcon and Bausch & Lomb. Dr. Davison is a consultant for Alcon. Dr. Waltz receives royalties from Bausch & Lomb and research support from AMO.