COVER STORY Choosing the Mode of Presbyopia Correction For true restoration of accommodation, the pupil dynamics and preoperative wavefront aberration profile must both be taken into account. BY DAMIEN GATINEL, MD he demand for presbyopia-correcting procedures has become more effective with newer-generation formulas increases every year in our practice. This is par- and modern interferometry-based biometric techniques. tially due to demographic factors, as the French Furthermore, if the refractive outcome after cataract extrac- population is aging, following the global trend in tion must be corrected, the presence of the LASIK flap mostT developed countries. The median age in France is interface facilitates the delivery of additional excimer laser now close to 40 years, which means that almost half of our ablation to fine-tune the refraction. Below I review several country’s population is experiencing some level of presby- categories of cornea-based correction. opia. Another reason for the growth in demand for pres- Hyperopic presbyopes. Hyperopic LASIK with slight byopia correction is that people of presbyopic age tend to overcorrection in the nondominant eye works well in gather and socialize with people of a similar age, who are hyperopic presbyopic patients. Even noncustomized or of course also presbyopes. Word-of-mouth recommenda- non-Q-value–optimized (ie, nonaspheric) hyperopic abla- tion is, therefore, more likely in this population than in tions generally induce some level of corneal multifocality younger patients, for whom myopic or hyperopic refrac- because of the inherent characteristics of positive abla- tive errors may not necessarily be a shared condition. tion profiles. These profiles tend to induce more negative If asked my preference for presbyopia correction, I spherical aberration than mathematically predicted and would say I have no preference other than to choose the can be used to provide both eyes of the same patient mode of correction that I feel is best suited for a specific with some level of multifocality (ie, slight in the dominant patient. In general, whenever the crystalline lens is clear eye and accentuated in the nondominant eye). Ideally, and the desired refractive condition (along with the the degree of multifocality and overcorrection should be ocular and corneal status) is amenable to excimer laser different for each patient, depending on visual needs. and/or corneal inlay correction, I would opt for this type Presby-LASIK programs. It is interesting to me that of technique and avoid clear lens extraction. This article some laser manufacturers try to differentiate and posi- presents some of my preferences for individual catego- tion their presby-LASIK–correction protocols with dif- ries of patients, along with insights gleaned over a career ferent names and claims of unique concepts, when, in of performing refractive surgery. fact, any such multifocal correction relates to the same principle: some increase in the magnitude of negative CORNEA-BASED PROCEDURES (or positive) spherical aberration, which provides the eye Overview. Corneal procedures are less invasive with multifocality. Although the specifics of these abla- than lens-based surgery, in my opinion. With corneal tion profiles may be proprietary or based on Q-values or approaches, it is possible to fine-tune or enhance the cor- aspheric shapes, they are ultimately aimed at inducing rection shortly afterward or even years later, if needed; in some positive spherical aberration (ie, near correction my experience, well-executed LASIK procedures enable in the midperiphery, distance vision in the center) or flap relifting as late as 15 years after the initial procedure. negative spherical aberration (ie, near correction in the Techniques such as LASIK, PRK, and small-aperture center, distance in the midperiphery). corneal inlays do not preclude performing cataract surgery The link between multifocality and higher-order when that becomes necessary. The argument that these aberration (HOA) is usually unstated; this may be due procedures will make cataract surgery outcomes less accu- to the fact that inducing specific HOAs is a paradigm rate is flawed, because postrefractive-surgery IOL calculation that seems in blunt opposition with the goal of cus- OCTOBER 2013 CATARACT & REFRACTIVE SURGERY TODAY EUROPE 1 COVER STORY tomized monofocal ablations, which aim at reduc- can read again without aid due to the development of ing the HOA level to increase the quality of vision. nuclear cataract and myopic shift (ie, lens refractive index Spherical aberration is not the only aberration that change) are potential candidates for multifocal IOLs. In these causes effective multifocality; rotationally asymmetric patients, monofocal IOLs can be unsatisfactory; although the multifocal IOLs such as the Lentis Mplus (Oculentis emmetropic correction brings clear distance vision, patients GmbH) use a combination of coma and trefoil aberra- may feel that their near vision has become blurry again. tions to induce some near addition power within the entrance pupil zone. These multifocal strategies must A RANGE OF TECHNIQUES offer some level of global spectacle independence and I have tried all the presbyopia-correcting techniques minimize the risks of glare and halos. for which I felt confidence in terms of their reproducibil- Previous RK. Patients who underwent radial keratoto- ity and conceptual mechanisms. I have tended to avoid my decades ago have now reached presbyopic age. In my techniques when I felt that there were too many uncon- experience, they can benefit from customized or noncus- trolled variables that could interfere with the final result tomized hyperopic PRK to reduce—sometimes dramati- and lower the chances of successful outcomes. cally—their spectacle dependence, although the results As an example, femtosecond intrastromal relaxing are less predictable in this patient category. Some of the incisions for presbyopia correction (Intracor; Bausch + operated eyes retain or exhibit useful multifocality due to Lomb Technolas) are not part of my armentarium for the persistence of irregularity at the corneal surface, and presbyopia correction. Even today, the location of the these eyes can eventually achieve good UCVA and BCVA. optimum center for these concentric incisions is debat- Myopic presbyopes. Caution is required in myopic ed. Furthermore, any intended centration strategy is (a) presbyopic patients, who are usually more demanding not easy to achieve and (b) impossible to adjust postop- regarding the quality of distance and near vision than eratively, and any technique based on the biomechanical hyperopes. In these patients, especially the low myopes, response of the cornea (eg, radial keratotomy, peripheral monovision should always be the first alternative to con- corneal collagen shrinking—both currently abandoned sider, and this should be simulated preoperatively using techniques) is subject to too many variables, such as contact lens trials as part of patient education efforts. intraocular pressure, the viscoelastic properties of the cornea, and the intensity of the wound-healing response. LENS-BASED PROCEDURES In contrast, I was an early adopter of the small-aper- The presence of significant lens opacification should ture corneal inlays (Kamra corneal inlay; AcuFocus, Inc.), logically orient patient choices toward lens-based as their mechanism—depth of field increase, similar to surgery. My favorite multifocal IOL platform—since I pinhole cameras—is well-established, and their adjust- codesigned its optical profile and characteristics—is the ability and reversibility have been demonstrated. FineVision trifocal diffractive apodized IOL (PhysIOL). Within the lens-based technique category, I have not been The recent trend toward use of computers and electron- convinced of the real restoration of some accommodation ic tablets for reading makes intermediate vision a legiti- with accommodating IOLs, and hence I no longer use them mate request and not a bonus reserved for patients with in my surgeries. Hopefully, improvements in design and specific activities such as playing and reading music. accommodation efficiency may occur and lead to a new and As with corneal laser corrections, in mild and high more effective generation of IOLs in the near future. myopes, monofocal IOLs should be considered. Patients I believe that there are no good or bad techniques, but who were previously emmetropic or hyperopic, who lately rather good and bad candidates for a specific surgical tech- nique. Matching the patient with the right technique is the TAKE-HOME MESSAGE main condition for the success of any refractive surgery. • With corneal presbyopia-correcting approaches, it is possible to fine-tune or enhance the correction LESSONS IN INDICATIONS AND shortly afterward or even years later, if needed; CONTRAINDICATIONS additionally, they do not preclude performing Several dissatisfied patients have been referred to me cataract surgery when that becomes necessary. after clear lens extraction and implantation with multifocal • The presence of significant lens opacification should IOLs. In most of these cases, the poor functional outcome orient patient choices toward lens-based surgery. could be explained by the operating surgeon’s lack of • There are no good or bad techniques, but rather attention to or ignorance of preoperative contraindications good and bad candidates for a specific surgical such as uncontrolled corneal astigmatism or undiagnosed technique.