Mixing Multifocal Cataract Lenses
(ReZoom and AcrySof IQ ReSTOR)
[Editor's note: In this article, former AllAboutVision.com editor Marilyn Haddrill shares her personal cataract surgery experience. Marilyn underwent bilateral cataract surgery in 2007, with implantation of multifocal intraocular lenses (IOLs) in both eyes: a ReZoom multifocal IOL in her right eye and an AcrySof IQ ReSTOR multifocal IOL in her left eye.]
After cataracts began significantly affecting my night vision in early 2007, I chose cataract surgery with implantation of a ReZoom multifocal IOL (Abbott Medical Optics) in my right eye and an AcrySof IQ ReSTOR multifocal IOL (Alcon Laboratories) in my left eye. I chose to "mix" multifocal IOLs for several reasons, including:
- I was aware of professional journal discussions among cataract surgeons indicating that certain qualified candidates potentially could benefit from a fuller range of vision when the ReSTOR and ReZoom multifocal lenses were combined.
- Most importantly, my cataract surgeon (Dr. William Fishkind of Tucson) recommended this approach.
Just before cataract surgery, I was highly myopic at -7 diopters in my right eye and -6 diopters in my left eye. I had worn glasses for nearsightedness since I was 6 years old and could never see the "big E" on the chart without correction. With presbyopia (inability to focus at all ranges) and cataracts added to high myopia, my visual function was degrading rapidly.
My original outcome following cataract surgery in 2007 was this:
- Right eye (ReZoom): 20/20 distance, 20/20 near.
- Left eye (ReSTOR): 20/20 distance, 20/15 near.
- With both eyes: 20/20 distance, 20/15 near.
I also had astigmatism in my right eye, which was corrected at the same time as cataract surgery with limbal relaxing incisions that slightly flattened the eye's surface. This procedure helped provide an excellent result in the ReZoom eye during the first year or so following cataract surgery. However, the astigmatism gradually returned.
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In my first follow-up eye exam about 18 months later, I had 20/25 distance vision in the left eye and 20/40 distance vision in the right eye a loss of two lines probably caused in part by the return of astigmatism. An eye doctor also told me that dry eye likely was a contributing factor. (More details are available in the two-year update below.)
In late 2010, I developed posterior capsular opacification (PCO) in both eyes a relatively common complication following cataract surgery that can be easily resolved with a YAG laser capsulotomy.
This procedure uses laser energy to create a clear opening in the posterior portion of the eye's natural lens capsule, which is located just behind the IOL and is left intact during cataract surgery. PCO is clouding of this membrane, which can occur weeks, months or even years after cataract surgery. PCO can occur with any kind of intraocular lens, including multifocal IOLs.
After I underwent laser procedures for PCO, my eyesight in late 2010 was this:
- Right eye (ReZoom): 20/30 distance, 20/40 near
- Left eye (ReSTOR): 20/25 distance, 20/15 near
- With both eyes: not measured.
More details related to how my vision has changed since the original surgical procedure are available in the two-year and four-year updates at the the bottom of the article. At this point, I remain a solid fan of mixing two lenses to combine their strengths as long as your cataract surgeon agrees this would be a good approach.
The following account was written right after I underwent cataract surgery in 2007.
Why Mix the ReZoom and ReSTOR Multifocal Lenses?
Not surprisingly, the two competing companies that market these two lenses think mixing them together is a bad idea. So do some cataract surgeons, based on discussions in professional journals.
But now that I've experienced these results, I fully understand why some cataract surgeons take this approach with qualified candidates. Each lens refracts light in a different way. Images are processed differently, depending on the way the "zones" are set up on each lens to enable simultaneous vision at near, intermediate and far ranges. This means that each lens performs differently in certain circumstances.
Ocular Surgery News and other trade publications recently have quoted eye surgeons who are interested in seeing companies develop pairs of intraocular lenses, with each lens having different characteristics. Once implanted during cataract surgery, the combined strengths of each lens then would contribute to better vision at all distance ranges.
Multifocal IOLs aim to offer a full range of vision (near, intermediate and distance), as in this simulation supplied by AcrySof IQ ReSTOR and Dr. William Fishkind.
Eye surgeons say this approach, creating a type of modified monovision, would take some of the "guesswork" out of using two different types of intraocular lenses, particularly when it comes to mixing and matching lenses manufactured by different companies.
Benefits I've experienced from the two lenses include:
- ReZoom. I could not work at the computer without the ReZoom eye, which so far is superior (though not perfect) for intermediate vision. In some situations, ReZoom is better for distance vision. But in other situations (primarily in low lighting), the ReZoom is less effective at distance.
Sometimes the ReZoom eye sees better for near vision, depending on the lighting and circumstances. The ReZoom lens is fine for normal reading, but so far does not work at all for extremely fine print. Still, with the ReZoom, I see 20/20 at near.
- ReSTOR. I could not function as well as I do in low lighting without the IQ ReSTOR lens, aspheric version. As an example, I can see digital clock displays in the dark with absolute clarity with my IQ ReSTOR eye. My television screen also is sharper with ReSTOR. Television watching is best with ReSTOR. I credit my IQ ReSTOR eye with easily spotting a rattlesnake on the trail two different times in dark, low contrast conditions of late evening.
The IQ ReSTOR lens provides exceptional ability to see the finest of fine print, but only in reasonably good lighting. The IQ ReSTOR is not so good for computer work (so far), but has actually improved in the intermediate range as I've adapted to both lenses. The ReSTOR, like ReZoom, is a great distance lens.
- ReSTOR and ReZoom Together. The IQ ReSTOR and ReZoom are learning to work together as a team. Actually, it's more like I'm adapting (eye to brain) to the two lenses and how they work together.
Some cataract surgeons are reluctant to implant two different lenses because a few people (like me) can't resist constantly "testing" each lens under different conditions, thus becoming somewhat obsessed. But as time passes, I've noticed that my best vision in most normal conditions, near and far, tends to result from the two eyes working together, and not so much from one lens being superior to the other.
Mixing Multifocal Lenses: The Results
If you are considering multifocal lenses, you must be prepared for the probability of a few relatively minor side effects unrelated to mixing lenses.
For example, I do see halos and mild starbursts around light sources at night. These "light shows" are gradually diminishing. I can now drive safely at night, especially considering what I experienced with cataracts and the huge starbursts they caused from oncoming headlights. I find wearing multifocals, even with night halos associated with both lenses, an acceptable tradeoff. Overall, my night vision now is significantly better in terms of seeing contrast and details. Of course, I naturally would prefer not to see halos at all.
In some indoor, low light conditions, vision is not perfectly sharp. If you use cameras, you might understand the analogy of taking a photo in "available light" versus using flash. Available light photos can be in focus, but they don't have the crispness of a photo taken with flash. Both types of images are focused and look good, though. So this is how I sometimes see through my multifocal IOLs in low lighting indoors as though the scene had been photographed in available light with a good, but not perfect, result.
Daytime distance vision is beyond excellent, however. I see better in the great outdoors than I ever have in my life, even in younger years. Details are intricate, from individually defined feathers on birds to the fine detailing of rock walls. I delight in being outdoors with my multifocal lenses, especially now that my bright color vision has been recaptured with the elimination of cataracts.
Near vision could be better, but it's acceptable. For example, I don't just automatically read tiny print. I need to adjust the distance first and then concentrate on reading extremely fine print. Regular reading is better, but requires adequate lighting. I would be out of luck trying to read a menu with fine print in a dark restaurant.
The ReZoom multifocal IOL is designed to deliver balanced view optics, according to the manufacturer. Diagram supplied by Abbott Medical Optics and Dr. William Fishkind.
I may need computer glasses eventually, just for the additional clarity. But I'm giving adaptation a try before turning to any kind of "crutch" for now. I spend many hours in front of the computer, so obviously I've been able to manage with the vision I have without eyeglasses.
The main point here is that I've functioned quite well for weeks now, at all distances, without needing eyeglasses. And I do believe that mixing the two currently FDA-approved multifocal lenses, the ReZoom and ReSTOR, is a good option for qualified candidates.
Had the two lenses not been mixed, I absolutely would have needed eyeglasses for reading fine print or for computer work. With this option, however, I can function comfortably and normally with the vision I now have even if I never wear eyeglasses again.
Following the eye exam, I discovered I had lost two lines of uncorrected distance vision in my right eye (20/40) with the ReZoom IOL and one-half line in my left eye (20/25) with the ReSTOR IOL. I also lost one line of uncorrected near vision in my right eye (20/30) and one line in my left eye (20/25).
These outcomes still are considered very good, but my vision clearly had declined from the excellent results recorded two years previously.
Because my vision clarity fluctuates, I thought I had a common cataract surgery complication that causes a "secondary cataract." However, both eyes were mostly clear of this type of problem. My retinas also looked healthy. My eye doctor instead suggested that fluctuations could be due to dry eye.
This makes sense, because I live in one of the driest areas of the United States. I also spend many hours in front of the computer, which certainly can contribute to dry eye.
A healthy cornea and tear film are important for sharp vision, particularly when you have multifocal IOLs. So my eye doctor suggested that I take flaxseed oil orally, and use lubricating eye drops. I noticed significant improvement within a week and now wish I could take those eye tests over again!
However, one lingering problem that cannot be corrected so easily is the return of almost one diopter of astigmatism in my right eye. While I had limbal relaxing incisions (LRIs) to flatten the cornea and rid that eye of astigmatism, the procedure did not last. So I always will have slight blurry vision in my right (ReZoom) eye now, due to astigmatism.
I do now use over-the-counter reading glasses for working at intermediate distances on my laptop computer. But most of the time, I still do not need to wear eyeglasses at all. Again, this is considered an acceptable outcome.
I also still have night vision problems including glare and halos, but these distortions are not severe and do not impede driving ability. Also, these visual distortions declined during the past two years as I adapted to seeing through multifocal IOLs.
Would I do the same thing with the options that were available in 2007 that is, mix multifocal IOLs? Yes, I would. I believe this was the very best option available for my particular vision correction needs at that time.
Would I do the exact same thing today? Probably not, because new FDA-approved versions of presbyopia-correcting IOLs now are available. Naturally I would consult with my eye surgeon first. But I likely again would select "modified monovision" through mixing different types of IOLs. This time, however, I would have the choice of Alcon's newest version of the ReSTOR, to enhance intermediate vision.
AMO also recently received FDA approval of the Tecnis multifocal IOL, which provides great near vision similar to the original version of ReSTOR. My impression of the ReZoom IOL now (unfortunately) is somewhat skewed by astigmatism. But I might consider combining the Tecnis with the ReZoom, based on an eye surgeon's opinion of what might work best.
If you and your eye surgeon are considering combining presbyopia-correcting IOLs, another option might be the newest version of Crystalens (Bausch + Lomb). The Crystalens is not a multifocal IOL, but instead shifts within the eye to "accommodate" or provide focus at multiple distances. A study reported in the American Journal of Ophthalmology (September 2007) demonstrated that an earlier version of the Crystalens provided good intermediate and near vision, with better contrast sensitivity and less chance of night vision problems.
In the future, look for FDA approvals of toric multifocal IOLs that also can correct astigmatism. These types of IOLs eventually might replace limbal relaxing incisions, which currently remain the best option for astigmatism correction combined with use of presbyopia-correcting IOLs.
At this time, I am happy with my vision while being somewhat disappointed in the return of astigmatism, which causes slight blurring in my right eye. Before this happened, the ReZoom eye had distinct strengths that no longer are as evident, such as sharper distance focus in certain lighting conditions.
Following laser procedures in late 2010 to correct a common cataract surgery complication that causes cloudy vision, my eyesight did generally improve from the two-year results except for the loss of one line of near vision in my right eye. Also, I have been regularly taking flaxseed oil orally to help control dry eye. My vision fluctuates in extremely dry, windy weather, so I definitely blame this on sporadic problems with dry eyes.
Again, at this time I am happy with my vision while being somewhat disappointed in the return of astigmatism, which causes slight blurring in my right eye. Before this happened, the ReZoom eye had distinct strengths that no longer are as evident, such as reasonably good intermediate vision and extremely sharp distance vision.
I do still see some halos and glare at night, but I absolutely think the ability to see reasonably well at most distances was well worth the tradeoff. I have extremely good near vision in my left eye, which is why I think some people might want to consider modified monovision through mixing a stronger near power IOL with one that offers better intermediate distance vision. I greatly value that ability to read extra fine print without glasses.
I definitely will consider a procedure to correct astigmatism in my right eye at some point in the future. I don't want to undergo LASIK for astigmatism, partly because I have somewhat of a problem with dry eyes. For now, I'm watching to see what happens as new technology develops.
Are You a Candidate for Mixing Multifocal Intraocular Lenses?
If you are a perfectionist, hard to please and have been satisfied with the vision (corrected or uncorrected) you have currently, you might not be a good candidate for multifocal intraocular lenses. You must be prepared for somewhat of a tradeoff, with the understanding that you are unlikely to fully recapture the kind of vision you had as a 20-year-old in exchange for potentially being able to see at all distances.
Remember that surgical outcomes vary, sometimes depending on surgeon skill and experience. Make sure you discuss with your eye surgeon all options that are available to you, as well as potential problems and complications. Be sure that you know what additional payment might be required if you need an enhancement, such as LASIK, following a multifocal lens implant.
The type of vision errors you have and your basic eye health also will determine whether you are a good candidate for mixing multifocal intraocular lenses. Keep in mind that all eye surgery has risks, some of them sight-threatening in rare cases.
[Page updated April 2013]