Identifying Successful Candidates for Premium IOLs

As he gained experience with them, this surgeon fine-tuned his approach to new-technology IOLs. Now, most of his patients benefit from the sharp vision they provide.

By Bret L. Fisher, M.D.

One of the keys to a successful premium IOL practice is identifying which patients are likely to benefit most from these exciting new technologies. This exercise in matching patients and technologies isn't necessarily new or unique to ophthalmologists, but it's never been as much of an issue in cataract surgery as it is today.

For years, the monofocal lens implant was the primary weapon in our armamentarium for restoring focus to the visual system following cataract extraction. Despite their advantages over aphakic spectacles and contact lenses, these prosthetic devices failed to provide the range of vision or functionality found in the healthy pre-presbyopic human eye. With the surge of the baby boomer generation into the presbyopic and cataract age groups, ophthalmologists, researchers and makers of medical devices have striven to produce an implant that would more closely approximate the function of the natural crystalline lens.

Today, aspheric, toric, multifocal and accomodative IOLs offer distinct benefits, and we as physicians are morally, and perhaps legally, obligated to consider and discuss with our patients the range of options available to them for restoring their vision. As these premium lenses are more commonly used and the public becomes more aware of them, we'll need to be able to speak and act knowledgeably about their use or we risk losing patients to those who can offer them these newer technologies.

In this article, I discuss my approach to matching my patients to the appropriate IOL. This approach has evolved as I've gained experience. You may be able to adapt some of these tools to your practice as well.

THE 'IDEAL' CANDIDATE

When I started using premium IOLs, I took an "exclusional" approach when evaluating a candidate for their use. That is, I began with the bias that any given patient was not suited for these implants until they had successfully weathered a lengthy checklist of reasons why they could not be included as a suitable candidate. This very cautious initial approach reflected my inexperience with these lenses and lack of firsthand knowledge about the tremendous benefits they could offer my patients.

As I've become more experienced with these new technologies, my approach has evolved to be "inclusional." I now consider every cataract patient a candidate for one of these implants unless something arises during the examination indicating a patient would not benefit from a premium IOL. While this distinction may seem subtle, the mindset is completely different, and my approach has been altered radically. I now strive to match each patient with the very best lens implant I can offer, given his or her lifestyle, desires, expectations, ocular health and other factors.

Who then, is an ideal candidate for a premium IOL? For a multifocal IOL, which is the most common lens upgrade in my practice, the ideal patient is one who:

■ Has no other significant disease of the eye or ocular system

■ Understands the options for visual rehabilitation after cataract surgery

■ Can give appropriate informed consent

■ Wishes to reduce or eliminate his or her dependence on eyeglasses.

That's it. Notice I didn't say anything about personality traits, occupation, financial status, night driving or extended computer use as qualifiers. Based on our results with the AcrySof^® ReSTOR^® Aspheric IOL, patients enjoy excellent distance, intermediate and near vision (Figure 1), with 90% reporting they never wear eyeglasses (Figure 2). Patients also report little difficulty performing a wide range of activities of normal living involving distance, intermediate and near vision (Figure 3).

Having now implanted more than 800 standard and close to 100 aspheric ReSTOR implants over the past 2 years, I can confidently tell my patients that I expect them to be very satisfied with this lens.

SOME EXCEPTIONS

The superior performance of the current generation of premium IOLs makes them an excellent choice for the vast majority of patients, and, in truth, most patients will be "ideal" candidates and should be offered this technology.

Which patients should not be offered premium IOLs or would benefit from one type of premium IOL over another? Because of the excellent and consistent results I've achieved with the ReSTOR aspheric lens in my practice, I don't offer or discuss other multifocal lens implants with my patients unless they specifically request another type. Similarly, my clinical experience as well as results reported by others show that spectacle independence is actually lower when different types of multifocal or blends of multifocal and accomodating or monofocal lenses are implanted.^1,2

Therefore, in determining which patients would be successful candidates for multifocal lens implants, I don't try to recommend a specific IOL based on a patient's lifestyle or visual demands, with one exception. If a patient's only visual complaint is difficulty with night driving, if he wants only the best uncorrected distance visual acuity, and if he doesn't mind wearing reading glasses, I'll offer an aspheric monofocal lens such as the AcrySof^® IQ lens, which has now been documented to improve night driving performance compared to a monofocal lens.³

Patients presenting for cataract surgery may have other issues, though, that would make them unsuitable for some or all of these advanced lens implants. For multifocal implants, I exclude any patient with significant optic neuropathy, including glaucomatous optic nerve damage, significant age-related macular degeneration (AMD), previous vascular occlusion or any retinal disease likely to reduce central visual acuity after surgery.

I use the lens with caution and extensive discussion, including the possible need for later IOL exchange, in patients with mild to moderate glaucoma, mild dry AMD, mild epiretinal membrane or previous branch retinal vein occlusion with good visual recovery. I counsel any patient with other abnormalities of the eye or visual system that a multifocal lens will tend to exaggerate these other problems and may negatively affect their vision at all ranges.

CORNEA CONSIDERATIONS

Similarly, the cornea can present a stumbling block when deciding who would be most appropriate for a multifocal or other advanced or premium lens implant. Patients with regular corneal astigmatism should be offered these lenses, as they do very well when their astigmatism is managed appropriately. I perform corneal relaxing incisions on approximately one-third of patients in whom I implant a ReSTOR aspheric lens, and an additional 6% receive excimer laser vision correction following implantation, either because of insufficient response to the corneal relaxing incisions, surgically induced or clinically significant residual astigmatism or, occasionally, as a planned staged procedure.

For patients with astigmatism and an abnormal cornea, such as those with form fruste, subclinical or frank keratoconus, a toric monofocal lens may be a more appropriate choice. I discuss with these patients my reasons for recommending they not receive a multifocal implant, as they may otherwise be disappointed or confused when they talk to friends or family members who have undergone cataract surgery with a multifocal implant and now no longer need to wear eyeglasses for reading.

Significant irregular astigmatism, central corneal scarring or opacity and marginal corneal degenerations causing instability of the cornea are all contraindications to implantation of a multifocal or toric lens, and the benefit of an aspheric monofocal implant may be less predictable in these patients. These corneal problems, like other forms of ocular disease, will tend to disproportionately impair the vision when challenged with multifocal optics.

The same may hold true for patients who have undergone previous radial keratotomy. Approach these patients with caution. I have had mixed results when implanting multifocal IOLs in patients who have undergone previous radial keratotomy. Although the cohort of patients in my practice is not large enough to do meaningful statistical analysis, my impression is that the final visual acuity is not as good, patient satisfaction is not as high, and the time required to reach visual stability is longer. However, because many of these patients are very highly motivated to be spectacle independent following cataract surgery, I will, with careful informed consent, offer selected patients the option of a multifocal lens implant.

In this setting, and in patients who have undergone previous hyperopic LASIK, I'll choose a standard ReSTOR lens, as the asphericity of the aspheric ReSTOR would tend to increase rather than decrease optical aberrations. For patients wanting a monofocal lens in this setting, I'll choose a neutrally aspheric premium IOL. Unlike patients who have had previous radial keratotomy, those who have undergone previous LASIK or PRK tend to do well with multifocal lens implants in my practice, as they are highly motivated to remain as free of eyeglasses as possible. With these and previous RK patients, I'm careful to discuss the difficulty, as compared to a patient with a virgin cornea, of performing accurate IOL calculations, and the possible need for IOL exchange or other fine-tuning after their cataract surgery.

For previous LASIK patients, being able to lift their flap and correct small residual refractive errors after implantation of a multifocal IOL is a plus. I believe this, combined with the absence of corneal scarring, contributes to the higher success rates for multifocal lens implants in these patients compared to those who have undergone previous radial keratotomy.

MEDICAL CONSIDERATIONS

A few medical issues would prevent a patient from having a successful outcome with a premium IOL. Connective tissue or autoimmune disease could interfere with the performance of incisional or laser-based approaches to correcting corneal astigmatism. These patients may be better suited for a toric implant, such as the AcrySof^® Toric IOL.

Previous cerebrovascular accident with significant loss of the visual field would lessen or negate the benefit of a premium lens implant. I've enjoyed great success in implanting ReSTOR aspheric lenses in patients taking tamsulosin HCl (Flomax, Boehringer Ingelheim) or another IFIS drug and do not consider this a contraindication to the use of this implant.

FRAMEWORK FOR SUCCESS

Obviously, other considerations, both ocular and medical, may need to be factored into our decision as to which lens implant is most appropriate for any given patient. My goal in this brief discussion was not to present a complete or exhaustive list of every issue that could arise in the process of examining and counseling a patient for surgery, but rather to give an overview and a framework for guiding the decision-making process.

One of the reasons that we, as anterior segment surgeons, necessarily charge a premium to offer these advanced lens implants is precisely because of the extra time, testing and consideration that goes into determining which candidates will be successful with these new and exciting technologies. Therefore, it's incumbent upon us to make every effort to identify which patients would benefit from these technologies and also do everything in our power to give them the best possible outcome.

With appropriate patient selection, use of these new and exciting lenses can be a very rewarding experience for you and your patients.

Bret L. Fisher, M.D., is a founding partner and currently serves as medical director of the Eye Center of North Florida in Panama City, Fla., where he specializes in cataract and refractive surgery.

REFERENCES

1. Mann PM, Brunson PB, O'Neal MR. Patient Survey of Visual Results with Presbyopic IOLs. Poster presented at ASCRS 2007, San Diego, Calif.
2. Moshegov, CN. Visual function with bilateral ReSTOR lenses versus unilateral ReSTOR and either Array or ReZOOM lens in the fellow eye. Free paper presented at ESCRS 2006, London.
3. AcrySof^® IQ IOL Package Insert SN60WF.