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Depth of focus a success factor with premium IOLs
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Multifocal IOLs offer patients a broader range of functional vision for performing daily activities.
When we discuss the option of premium IOLs with our cataract patients, we typically mention that a major advantage for qualified patients is the ability to see simultaneously at multiple distances. This is often overlooked.
But we also should inform patients that premium IOLs such as the Tecnis multifocal (Abbott Medical Optics) and AcrySof IQ ReStor (Alcon) can increase functional vision by providing superior depth of focus, particularly in circumstances in which adequate light is present. More studies are needed to determine the scientific validity, but anecdotally, my patients are strongly in favor of their new vision, which allows them more stability.
For example, older patients are sometimes prone to falls that can have serious consequences, such as hip fractures. To help avoid falls, patients must rely on stereopsis and depth of focus to see objects in relation to each other.
This issue particularly is of concern at our California practice because multistory residences are the norm in the area (land is not cheap here). To safely accomplish daily activities and chores, our older cataract patients who are vulnerable to falls need the ability to clearly see all the steps of stairways and in proper relation to each other. These patients often live alone and must maintain independence of some fashion.
We have now studied these issues for about 5 years and have found that, particularly with an aging population, premium lenses have a huge role to play because of the variables involved with quality of vision. We continue to refine questionnaires for subjective input from patients, in addition to creating other types of clinical assessments to clarify the relationship among stereoscopy, functional vision and premium lenses.
When we compare vision correction options for most cataract patients, multifocal IOLs at this time seem best able to enhance daytime functional vision in at least three dimensions. It is also true, however, that multifocal IOLs can decrease contrast sensitivity in low lighting conditions, which is why we must also counsel our patients about the need to use adequate lighting. This is always a good safety tip for our older patients, even if they are not good candidates for multifocal IOLs.
Enhancing functional vision
With bifocals and trifocals, the brain first must select where to look (near or far). Because the patient cannot perceive multiple distances simultaneously, this can have a detrimental effect on the ability to make quick visual assessments and react accordingly. Compared with eyeglasses, multifocal IOLs give the patient the advantage of a stable and full visual field, including at the periphery.
Communication is the key
Surgeons must believe in the products they discuss. One reason we have a higher conversion rate in our practice is because I believe so strongly in the technology represented by premium IOLs. This confidence and passion for the technology are conveyed in all my discussions with patients. I never try to “sell” a patient on premium IOLs, but I do believe each patient has the right to be fully informed about risks and benefits represented by new technology, especially when that technology might improve functional vision beyond any other options that are currently available.
In addition to positioning premium IOLs well within the practice, however, effectively communicating the benefits of improved functional vision might even help patients who are unhappy with their premium IOL outcomes or those who have good postoperative visual acuity but say they are unhappy with their premium lenses.
First, I recognize these patients may not have been aware that whatever natural multifocality they had before surgery would be forever lost after their natural lens was removed. Patients may not fully grasp the meaning of what sight would be like with a monofocal IOL compared with a multifocal IOL. I show them what true monofocality looks like by placing a pair of –2.5 D spectacles on them to duplicate the sight a monofocal IOL provides — typically, excellent distance vision and extremely blurry near vision.
Once patients see for themselves what a monofocal IOL really is and the limitations in how they will view the world for the rest of their lives, they have a much better perspective. They also are better able to appreciate the fuller range of vision that a multifocal IOL provides, even if there are certain side effects such as mild glare and halos at night. It is important to inform patients that these same side effects also can occur with monofocal IOLs but that they are more likely to occur with multifocal IOLs.
Of course, multifocal IOLs are not right for all patients. I would never advise use of multifocal IOLs for a truck driver whose occupation depends on many hours of night driving. And for those patients who do opt for a multifocal IOL, I caution them to be extra careful while driving at night.
For most patients, however, we have found the benefits of multifocality and improved functional vision tend to outweigh any possible side effects related to glare and halos.
Lens selection
I prefer multifocal IOLs, namely the single-piece Tecnis and ReStor multifocal IOLs, but I do use all of the premium lenses in my practice, including the Crystalens (Bausch + Lomb). This lens provides reasonable blended vision; however, I am not convinced it gives the same stable, around-the-clock consistency and range of vision as multifocal IOLs.
In my opinion, the material and aspheric optics of the Tecnis platform are unmatched in terms of the ability to provide sharp, full-color vision. I have also developed a great deal of confidence in the ability of the Tecnis multifocal to meet the expectations of patients who want excellent near and reliable intermediate vision. For distance, both the Tecnis and AcrySof also have the ability to correct low levels of spherical aberrations, which improves functional vision in conditions such as night driving.
Of course, the prospects for new and continuing improvements in IOLs continue. While multifocal IOLs achieve excellent outcomes, they are based on principles that divide light into multiple foci, which is physiological. This technology does not duplicate the way the eye sees naturally and therefore has certain limitations.
We look forward to adopting even newer technology as it becomes available, such as dual-optic accommodating IOLs, which will provide more physiologic vision and better contrast sensitivity. For now, however, the current technology of new-generation multifocal IOLs offers cataract patients a much fuller range of vision than previously possible.
Ehsan Sadri, MD, FAAO, FACS, can be reached at Atlantis Eyecare, 361 Hospital Road, Suite 327, Newport Beach, CA 92663; 949-642-3100; email: esadrii@gmail.com.
Disclosure: Dr. Sadri has no relevant financial disclosures.