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Pro: Combining dissimilar presbyopia-correcting IOLs can work in select patients
Using different presbyopia-correcting IOLs in two eyes of the same patient can meet some individuals’ needs, one surgeon says.
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| Richard L. Lindstrom |
Combining two dissimilar IOLs in the two eyes of the same patient can be an effective strategy for correcting presbyopia, according to Richard L. Lindstrom, MD. In certain patients, the use of two different presbyopia-correcting IOL models may achieve better results than two of the same lens, he said.
In an interview with Ocular Surgery News, Dr. Lindstrom said there are many available IOLs, including regular and aspheric monofocal lenses, two new multifocal lenses and an accommodating IOL, which lend themselves to several combination because each lens has different qualities. He said surgeons must be aware of each IOL’s strengths and weaknesses when using them in combination.
“There are some people who say that combining lenses is not a good idea,” Dr. Lindstrom said. “My position is that they’re wrong and that there’s a lot of experience accumulating to show that they’re wrong. More and more surgeons are getting comfortable with it.”
Surgeons who advocate against the practice of mixing lens styles are doing so because they do not feel it should become the standard of care. See the article on the opposite page for the conflicting viewpoint.
The practice of combining different lenses in two eyes of the same patient is not new in ophthalmology, Dr. Lindstrom noted. The concept of monovision, in which one eye is corrected for distance and one eye for near, has been used safely and effectively for years with contact lenses as well as IOLs, he said. Another widely used strategy is what Dr. Lindstrom called modified monovision, in which a standard or aspheric monofocal lens or an accommodating lens is used in one eye and a multifocal in the other.
“We know that most patients adapt to these strategies very well,” he said.
Real world application
Dr. Lindstrom said most surgeons have a preferred IOL technology that they typically use for patients with a particular refractive goal. He said it is helpful to ask patients their goals for their vision after surgery and to base IOL choice on the patient’s preferences.
For instance, if a patient says he would prefer to see better at distance and in the intermediate range, Dr. Lindstrom said he would most likely recommend the accommodating crystalens IOL from eyeonics or the Advanced Medical Optics ReZoom lens in the patient’s first eye. If the patient expressed a desire for the highest quality reading vision, then Dr. Lindstrom said he might recommend a multifocal IOL such as the Alcon AcrySof ReSTOR apodized diffractive IOL or the AMO ReZoom in the first eye.
In his practice, cataract surgery for a patient’s second eye is typically scheduled for 2 to 4 weeks after the first eye, Dr. Lindstrom said, giving the patient an opportunity to experience the vision with the chosen lens. Based on the patient’s reaction, the surgeon can then assess whether to use the same lens in the second eye or to select a complementary alternative lens design, he said.
In 80% to 90% of cases, the patient is satisfied, he said, and the same IOL design can be used in the second eye. However, if the patient has an issue with the implanted lens, then selection of different IOL for the second eye may provide a better outcome and a happier patient, Dr. Lindstrom said.
For example, in a patient following multifocal implantation with significant complaints of night vision symptoms, poor quality distance vision and weaker than desired intermediate vision, selection of a crystalens or aspheric monofocal IOL for the second eye would be a reasonable option, he said.
“It’s a logical approach,” he said. “I’m not recommending that every patient get dissimilar lenses, and I think most patients are probably going to be happy with the same lens in both eyes. In the real world of clinical practice, if you put a technology in one eye and the patient is very happy with it, you’re naturally going to put that technology in the second eye. But if you do have a patient who is unhappy and has a deficit, with the multiple technologies we have now, you can often fill in that deficit by using a different lens in the second eye.”
Drawbacks of multifocals
Dr. Lindstrom said that for presbyopia correction with contact lens wear, the most frequently chosen modality is monovision, or blended vision. The second most popular choice is modified monovision, with a monofocal contact lens in one eye and a multifocal in the other.
The least common contact lens option selected by patients for presbyopia correction is a multifocal contact lens in both eyes, Dr. Lindstrom said. He said that is because multifocal lenses have certain drawbacks, in IOLs as well as contacts.
One disadvantage of multifocal lenses is that there is a reduction in quality of vision (contrast sensitivity) in distance, intermediate and near images because the lens is dividing the available incoming light between the two or three foci, he said.
A second disadvantage of lenses that are bifocal is that they tend to provide poor intermediate vision, he said. Patients can have good distance and near vision, but in those who have a lens with only two foci the intermediate distance may be less than satisfactory, in both IOL and contact lenses, he said. A third disadvantage is that all multifocal lenses generate unwanted night vision symptoms such as glare and halo, he said.
“So if you put one of these lenses in both eyes of your presbyopic patient, they may notice there’s a reduction in the quality of vision. They also may notice night vision symptoms,” Dr. Lindstrom said. “But if you put a multifocal lens in one eye and a monofocal or accommodating IOL in the second eye, you can have a significant reduction in the visual impression of reduced quality, much as you do in monovision, and you have less night vision symptoms. This idea is well established in the contact lens world. I and others are finding this premise, that dissimilar lenses can be used in the two eyes of an individual patient, to be as true in the IOL field as it is in the contact lens field.”
Available lenses
Two multifocal IOLs are currently available in the United States: the Alcon ReSTOR lens and the AMO ReZoom.
The ReSTOR, an apodized diffractive lens, provides “the best near vision of any of the multifocal IOLs,” Dr. Lindstrom said. But The ReSTOR may not perform as well at intermediate because none of the light is specifically focused for intermediate distance, he said.
The ReZoom zonal aspheric refractive IOL is a distance-dominant lens, Dr. Lindstrom said. The ReZoom lens gives better distance vision than the ReSTOR at most pupil sizes because the central 2.1 mm of the ReZoom optic is devoted solely to distance, he said. Near vision is, however, weaker than with the ReSTOR, he said.
“A reasonable combination, looking at the optics, would be to use a ReZoom and ReSTOR together, and some surgeons are doing that,” he said.
The crystalens, an accommodating IOL, provides high-quality distance vision and good intermediate vision, Dr. Lindstrom said, but may be “somewhat weaker” at near. The combination of the accommodating lens in one eye and a multifocal lens in the other can be “quite effective,” he said.
For Your Information:
- Richard L. Lindstrom, MD, is the Chief Medical Editor of Ocular Surgery News. He is in private practice at Minnesota Eye Consultants, 710 E. 24th St., Suite 106, Minneapolis, MN 55404-3810; 612-813-3600; fax: 612-813-3660; e-mail: rllindstrom@mneye.com. Dr. Lindstrom is a consultant for Advanced Medical Optics, Alcon, Bausch & Lomb and eyeonics.
- Erin L. Boyle is an OSN Staff Writer who covers all aspects of ophthalmology.