EyeWorld Asia-Pacific June 2018 issue

12 EWAP FEATURE June 2018 “ There is always hope for improvements in biomateri- als. The goals are something that is as optically pure as possible and has the longest lifespan possible, so it doesn’t show any signs of degradation. ” - Jonathan Rubenstein, MD a way-in-advance, special-order basis. The lenses could be sitting on a shelf at the manufacturer and be shipped quickly when we need them,” Dr. Miller said. “Alterna- tively, they could be manufactured to order. I would love to see lenses go up to 65 D or 70 D on the plus side. In the other direction, the lowest negative power foldable lens is –5 D. I would love to see a –10 D or –15 D. In fact, I’d like to see them go to –20 D in a single-piece design with an appropriately large diameter optic and large haptics,” he said. It would also be helpful to have IOL powers in smaller diop- ter increments. “The next hope is that if companies can produce a lens implant with a material that is optically very precise, maybe we can go from 0.5-D steps to 0.25- D steps,” Dr. Rubenstein said. “As there’s been more hope for refrac- tive neutrality, producing post- operative results with minimal to any refractive error, there’s been some hope that going to a smaller refractive step might make a dif- ference. There may or may not be value in that. Clinically, when I see a patient who has 0.25 D residual refractive error or is 0.25 D off the intended refractive error, that usually is clinically insignificant. I think this is a goal worth pursuing, but I’m not sure whether it has true strong clinical value or not.” Dr. Koch added, “In toric IOLs, we are getting close to the point where we could benefit from something that’s less than 1 D. I think the time may be coming for a 0.75 D or a 0.6 D toric because we’re doing a better job measuring and understanding both anterior and posterior corneal astigmatism. Also, I agree with Dr. Rubenstein that our IOL calculation accuracy is becoming so good that we could improve outcomes if we had IOLs in 0.25-D steps.” Delivery systems New IOL delivery systems are also on the way. “The advent of preloaded IOLs is a wonderful ad- vance for us,” Dr. Koch said. “But most of the preloaded lenses still have little quirks with their injec- tors, so I’m looking forward to see- ing some new advances in that area. Alcon has a new injector called AutonoMe that has a CO 2 cylinder and is incredibly slick. I don’t see advances in injectors as critical, but any time you can use a preloaded IOL injector, it’s a plus.” None of the multifocal IOLs come preloaded, Dr. Miller said. “We still have to load these lenses Views from Asia-Pacific Chul Young CHOI, MD Professor, SungKyunKwan University, Kangbuk Samsung Hospita l 29 Saemunan-Ro, JongNoGu, Seoul, South Korea Tel. no. +82-10-5091-8121 Fax no. +82-2-2001-2262 sashimi0@naver.com T here have been tremendous developments in IOL technology over the past few decades, but there have also been several unhappy incidents. Regarding the material of IOLs, as we have experienced, the calcification of hydrophilic IOLs has been a long-standing situation. Recently, with the development of posterior lamellar keratoplasty (DMEK and DSAEK), opacifications of previously inserted hydrophilic IOLs were reported in the lamellar surgeries. They concluded that the exogenous instillation of air and gas during the operations could have been the causes. Glistening formation in IOLs has also mattered for a long time in some hydrophobic materials, and many of us have had a hard time with the problem. Because of these experiences, many cautious eyes are watching for new materials and products, because they could be a matter of lifelong trust. “ There have been tremendous developments in IOL technology over the past few decades, but there have also been several unhappy incidents. “ ...Because of these experiences, many cautious eyes are watching for new materials and products, because they could be a matter of lifelong trust. ” - Chul Young Choi, MD The extreme range of power may matter to some patients; usually there are few available options. But there are more complicated situations regarding the dioptric steps of IOLs. As we know, there are several inevitable factors which can affect the postoperative refraction. First, the present tolerance limit for spherical dioptric power of IOLs from manufacturers is ±0.4 D, ranging from 15 to 25 D. However, the situation is not simply caused by IOL manufacturing technology; there are also many other inevitable problems we cannot avoid during the surgery with the modern technology, such as measurement errors in K values, physiologic decentration of IOL in the bag, SIA on anterior/posterior K, and individual differences in pupil size. Therefore, smaller refractive steps would not be of high value in reality. All these issues could have much stronger impact on premium IOLs, which require much higher precision, because there is no way to avoid or control the previously mentioned sources of error completely. This could be the reason why the much more tolerant IOLs in many situations, such as EDOF and trifocal IOLs, are popular these days. Editors’ note: Dr. Choi declared no relevant financial interests. Current state – from page 11