Eyeworld

EW REFRACTIVE SURGERY 42 February 2016 by Matt Young and Gloria D. Gamat EyeWorld Contributing Writers measures] are tradeoffs in terms of corneal aberrations to achieve pres- byopia correction. How much can you enhance depth of field—that is the question. Although experts have been working on the algorithms for more than 10 years, we still need to see the impact of that." "I'm an optical purist, and I think there should be a good indication for interfering with [the cornea]," said Simon J. Dean, FRANZCO, Eye Institute, Auckland, New Zealand, in an interview with EyeWorld. "A good optical system to get both near and distance always includes a compromise; you can do a monovision correction or do it as a multifocal on its own—either way you are going to lose clarity," he said. "To achieve satisfactory out- comes, presbyLASIK needs a thorough patient screening, good expectation management, careful planning, and highly accurate laser application," they said. "PresbyLASIK is not a new idea," Dr. Ahmed said. "It has been going on for some time, but at this point in time, we haven't seen the dramatic results we were hoping for with presbyLASIK. I'm encouraged by the R&D in it, though," he said. While it is indeed a great time to witness all the action on presby- opia correction, Dr. Ahmed noted, each of the potential corrective procedures, including presbyLASIK, has its own limitations. "Results I have seen have not been consistent," he said. "Bio- mechanics [and other outcome provide good near vision but re- duced far vision, which translates to a compromised safety," they said. On the other hand, peripheral presbyLASIK seems to provide good far vision and safety, while sacrific- ing near vision. "These findings make sense, as the central cornea is mostly respon- sible for the refractive performance of the eye," the authors explained. "Finally, laser blended vision seems to have no major drawbacks, providing good far and near vision combined with a good safety," they added. The authors emphasized that because presbyLASIK is a more demanding and time-consuming procedure compared to other regular refractive surgery, there are a lot more factors that need careful con- sideration. S ince Ioannis Pallikaris, MD, PhD, professor of ophthalmology, School of Medicine, University of Crete, Greece, performed the first LASIK procedure on a hu- man eye in 1989, the rest, as they say, is history. The popularity of LASIK among ophthalmic surgeons and patients alike is perhaps still unsurpassed by any other elective refractive correc- tion procedure available today. Beyond that, other modern refractive procedures were born out of fine-tuning the shortcomings of LASIK. It's fair to say that LASIK helped open the door in ophthal- mology for these new procedures. Meanwhile, due to the com- plexity of its mechanism and causes, presbyopia remains the most challenging visual defect to correct. We now have presbyLASIK making a buzz in the ophthalmic world as a potential approach in the correction of presbyopia. "Presbyopia is the real holy grail—an unmet need in refrac- tive surgery," said Iqbal "Ike" K. Ahmed, MD, assistant professor, University of Toronto, Canada. "At this point in time, all efforts, whether in laser, inlays, or IOLs, are attempting on some level to correct presbyopia." In a recently published paper in Current Opinion in Ophthalmology, Dr. Pallikaris and colleagues reviewed the potential of presbyLASIK in correcting presbyopia. The review was based on peer-reviewed papers published up to December 2014 about LASIK treatments with special ablation profiles intended for the treatment of presbyopia. "PresbyLASIK is an attempt to replace the dynamic process of accommodation with a static modi- fication of the corneal surface. This discrepancy between dynamic and static is the reason why presbyLASIK, together with other presbyopia 'treatments,' must be a compromise and cannot restore accommodative functionality together with high visual acuity and quality of vision at all distances," they reported. In their review paper, Pallikaris and colleagues compared the 3 treat- ment modalities in presbyLASIK. "It can be noticed that central presbyLASIK shows a tendency to PresbyLASIK for presbyopia correction

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