Eyeworld

EW INTERNATIONAL 84 May 2016 by Stefanie Petrou Binder, MD, EyeWorld Contributing Writer are not available. According to Francesco Carones, MD, director, Centro Oftalmo-Chirurgico Carones, Milan, Italy, who spoke on RLE at the meeting, patient selection needs to be very clearly defined. PRELEX: Purely refractive Presbyopic lens exchange (PRELEX) refers to a surgery designed to dras- tically reduce or eliminate the need for glasses at all distances. Unlike the use of RLE in ametropia, PRELEX targets plano refraction. "The most important aspect regarding refractive lens exchange in presbyopic patients is having the means to achieve plano through the use of accurate biometry and ker- atometry, the appropriate formula, cylinder management, customizing surgical factors, and performing sur- gical touch ups. Without this ability, PRELEX will not be successful," Dr. Carones said. The success of PRELEX is given by achieving spectacle indepen- dence, high quality of vision, and the absence of complications and side effects. To achieve individual- ized results, surgeons require sophis- ticated resources as well as the right IOL choice. Spectacle independence and quality of vision According to Dr. Carones, multifocal IOLs—trifocals in particular—pro- vide higher spectacle independence than any other IOL. They are more likely, however, to induce halos and night vision disturbances, and are very sensitive to the target refractive outcome. The surgeon must provide plano for best outcomes. Extended depth of focus (EDOF) IOLs give the best results for inter- mediate to distance vision. They rep- resent the best compromise between spectacle independence and quality of vision. Reading at near may be somewhat worse than with trifocals. "EDOF IOLs are very forgiving as to refractive outcome, which is one of their biggest advantages, making it much easier to achieve plano. There is a relationship be- tween spectacle independence and quality of vision—the higher the spectacle independence, the lower the quality of vision that we pro- vide the patient, unfortunately," Dr. Carones said. systems, Dr. Grabner noted that there is a certain degree of uncor- rected distance visual acuity loss. Other "secrets" shared by Dr. Grabner at the ESCRS meeting included, "When you implant a low refractive index implant, you need a higher curvature and therefore have to use the pupil near reflex to create a central island. What many sur- geons may not know is that you can use a hydrophilic microlens implant that has a higher refractive index of 1.4583, which allows you to implant deeper in the cornea." Small aperture inlays are opaque and ring shaped with a central aperture, and use pinhole optics to improve near vision by increasing the depth of focus. Dr. Grabner re- vealed that results for both near and far vision were very satisfactory in large studies, but cautioned surgeons to keep in mind that the increase in hyperopia that comes with increas- ing age (a change in lens shape) requires surgeons to set postop refraction at –0.5 D to –0.75 D below "plano" target. This achieves and maintains good uncorrected dis- tance and near VA, as the principle works both ways, distant and near. Refractive lens exchange (RLE) RLE, the removal of the transparent crystalline lens in exchange for an IOL implant, is performed in pa- tients with presbyopia with or without ametropia, as well as in patients with high ametropia at any age, as a rehabilitative proce- dure, when other surgical options Micro-monovision: Stereo acuity intact Laser-blended vision sets a patient's dominant eye for distance vision and the non-dominant eye for near vision, after increasing the depth of field for each eye through changes in the spherical aberration. Stud- ies have shown that monovision created through laser-blended vision resulted in 20/20 vision in 95% of myopes, 77% of hyperopes, and 98% of emmetropes, with minimal compromise to contrast and night vision. The procedure is well toler- ated by more than 95% of patients, and functional stereo acuity is maintained, making this relatively new technique, developed by Dan Reinstein, MD, promising, Dr. Grabner said. Intracorneal inlays: Set target with hyperopia in mind According to Dr. Grabner, intracor- neal inlays offer the advantage of be- ing tissue-sparing, extraocular, and removable. Nonetheless, primary challenges include biocompatibil- ity, effective optics, and stable and predictable results. Two promising versions include microlens system refractive corneal inlays and small aperture (depth of focus) inlays. Refractive corneal inlays have a central plano zone, surrounded by multiple rings of progressively increasing dioptric power, creating a multifocal effect. While near visual results have been good in emme- tropic presbyopes using microlens T reating presbyopia in the cornea necessitates surgical options that are reliable, ef- ficient, low-risk, reversible, adjustable, and stable over the long term. The problem is that these criteria can be hard to fulfill as a whole. "The first secret I will share with you about treating presbyopia in the cornea is that no technique is perfect, and there is always a compromise. Patient selection and expectation management are crucial. And if ever in doubt, avoid surgery," said Günther Grabner, MD, Univer- sity Eye Clinic, Paracelsus Medical University, Salzburg, Austria, who spoke on presbyopia correction in the cornea at the symposium "Are there any untold secrets in refractive surgery?" during the 20th Europe- an Society of Cataract & Refractive Surgeons (ESCRS) Winter Meeting in Athens, Greece. PresbyLASIK: Have an exit strategy Multifocal LASIK, or presbyLASIK, is a laser procedure that reshapes the cornea to create different power zones for seeing at varying distances. Although off-centered presbyLASIK ablations have been abandoned, central ablations have shown very good results, but not in all eyes, ac- cording to Dr. Grabner. Center near presbyLASIK gives good near visual outcomes but reduced distance vision and somewhat compromised safety, as about 2 lines of best cor- rected distance visual acuity can be lost in a significant number of cases. On the other hand, peripheral near presbyLASIK creates good distance vision with good safety outcomes, but with reduced near visual acuity. For those searching for the perfect solution, Dr. Grabner said, "Something that everyone should be aware of is that there is a dynamic process in the eye that we have to model with a static treatment— and therein lies the compromise. PresbyLASIK requires an exit strat- egy, especially in myopic patients who require retreatment in rough- ly 28% of cases. Unfortunately, long-term study results are largely lacking; therefore, careful patient selection and expectation manage- ment play a crucial role." "Untold secrets" revealed at ESCRS The KAMRA intracorneal inlay Source: Günther Grabner, MD Presentation spotlight

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