Eyeworld

EW FEATURE 92 Advances in corneal inlays • March 2017 cant time and energy to determine the best solution for each patient." One-eye procedure Satisfying a presbyopic patient with a one-eye procedure can be extremely challenging. Presbyopia is a problem of the crystalline lens, which Dr. Kugler thinks would ideally best be solved at its source— the lens. However, for people in stage 1 DLS, or individuals in their early to mid-40s, replacement lenses offer a suboptimal substitute for the natural, crystalline lens in good working condition, leaving surgeons reluctant to remove it. This is where treating a lens-based problem from within the cornea with corneal inlays or monovision becomes an interesting alternative. Dr. Kugler explained, "It is a challenge to fix a presbyope with a one-eye procedure, largely because we are not fixing the problem at its source. However, we do know from decades of monovision that monovi- sion is a very well tolerated solution, whether it is created by LASIK or by an IOL, provided that it is done appropriately. I think that in 2017 our definition of near vision is very different from what our definition of near vision was 20 or 30 years ago. People are using computers, cell phones, and tablets at a different distance than they once needed to see the things they were looking at up close. Even occupational ac- tivities have moved to more of an intermediate range than they once were." According to Dr. Kugler, inter- mediate vision is more important today than true near vision. This benefits monovision and bene- fits corneal inlay patients because patients with corneal inlays can achieve good vision in the interme- diate range. Monovision tends to be more challenging when near vision is too strongly targeted, resulting in too large a difference between the near and distance eyes. Dr. Kugler noted that the visual cortex of most patients responded poorly to the large gap between near and far tar- gets. "Monovision with an interme- diate target is very successful, and corneal inlays are excellent for the intermediate range with less com- promise of distance than standard monovision. Therefore, I think that although it still remains a challenge to satisfy a lens-based problem with a cornea-based solution, the point a picky patient. He elucidated, "I don't use these on everyone. I have patients who are laid back, who listen, and who are interested in having inlays, and I will usually do the surgery because I am com- fortable with their personality. I will do a 1 D loose lens test, and I might move forward with the operation if I am not dealing with a perfectionist, even if the patient opts to not do the contact lens test." Patients with high standards and expectations may not be suit- able for this particular solution to their eye problems. A patient who has never needed glasses before may expect too much. "If the patient is a perfectionist, I am going to recon- sider doing any corneal correction of presbyopia, in general," Dr. Thomp- son said. "But if he is pushing me to do it because he does not want reading glasses and is uncomfortable with a lenticular approach like a refractive lens exchange, then the contact lens test takes on a very im- portant role. I might suggest it for a longer period of time, and sometimes I'll do it at 1.25 D, pushing it just a little bit with a perfectionist patient who doesn't necessarily want to take my rec- ommendation. That is the art of refractive surgery and working with the various personalities." Eye dominance Eye dominance testing is an import- ant part of planning a corneal inlay correction, with the non-dominant eye generally corrected for near and the dominant eye for distance. A pristine distance correction is of key importance, according to Dr. Thompson, who tries to achieve plano refraction in the dominant distance-corrected eye at all costs. "I tell patients they may need PRK or LASIK to take their refractive error to plano in the eye that is going to be their distance eye. It is important for patients to know that off the bat, and while the idea of additional sur- gery is troublesome, their happiness is increased later with making sure that the dominant eye is corrected to plano," Dr. Thompson said. For Dr. Kugler, each patient needs to be carefully assessed for near and distance correction desig- nations. He explained, "Experience with LASIK and monovision lens procedures over several decades now illustrates that eye dominance is very important. Dominance varies from person to person and varies by degrees—some people are strongly dominant, some are weakly domi- nant, and some are cross dominant. If someone is cross-dominant and you measure their dominance 10 times you might get a different reading six of the times. I think it is important to emphasize the domi- nant eye for distance but realize that there are exceptions. This is another example of why there is not a cook- book recipe for how this is done. Refractive surgery cannot put people into a certain bucket. It is much more complex and requires signifi- for people who struggle with near vision in DLS stage 1, which means they have a clear lens. Once some- one gets into the second stage of DLS, then refractive lens exchange is a better option. But for someone with a clear lens who wishes to have a better depth of field for near vision, corneal inlays are an option," Dr. Kugler said. Dr. Kugler does not implant cor- neal inlays in people in DLS stage 2 or beyond. He prefers refractive lens exchange rather than corneal inlays for high or moderate hyperopes be- cause refractive lens exchange offers more permanence in these individu- als by addressing both distance and near vision in one procedure. Other contraindications to corneal refrac- tive surgery include dry eyes, thin corneas, corneal pathologies like keratoconus, irregular astigmatism, and autoimmune disease. Condi- tions that make for a poor corneal refractive surgery candidate will typ- ically make for a poor corneal inlays candidate as well, Dr. Kugler said. Personality Apart from a presbyopic patient passing muster for the inclusion criteria for corneal inlays, Dr. Thompson thinks that a patient's personality can strongly influence his decision making. Experienced refractive surgeons develop an un- derstanding of personality types in terms of whether or not their expec- tations are realistic and may deny a procedure that is bound to disap- Choosing continued from page 91 Raindrop flap up with inlay and dimensions Source (all): ReVision Optics continued on page 94

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