EyeWorld India December 2019 Issue

44 EWAP DECEMBER 2019 REFRACTIVE accuracy and stability to the toric IOLs 3,4 ,” he said. “Therefore, we should use a toric IOL whenever we can. Of course, in the U.S. the lowest power toric IOL is either 1.25 D (Envista and Trulign Toric [Bausch + Lomb]) or 1.50 D (AcrySof [Alcon] or Tecnis Toric [Johnson & Johnson Vision]), which translates to about 0.90 D or 1.00 D of corneal cylinder, respectively.” Due to a tendency for posterior corneal astigmatism and drift to ATR cylinder, Dr. Raviv said that they, on average, “place more toric IOLs around ̅i £nä‡`i}Àii >݈à >˜` more relaxing incisions at the ™ä‡`i}Àii >݈à œÀ œLˆµÕi >݈ð» Dr. Koch again made allowance for individual surgeon experience, saying that the choice between relaxing incisions and toric IOLs “depends on one’s comfort level with both technologies. In my practice, I perform relaxing ˆ˜VˆÃˆœ˜Ã ˆv ̅iÀi ˆÃ qä°Îqä°x œv >}>ˆ˜Ã̇̅i‡ÀՏi >Ã̈}“>̈Ó] ä°Îqä°Ç œv œLˆµÕi >Ã̈}“>̈Ó (depending in part on the orientation of the astigmatism versus my incision location), >˜` ä°nq£°x œv ܈̅‡Ì…i‡ÀՏi astigmatism. Anything above that is treated with a toric IOL.” Enhancements Despite surgeons’ best efforts, they are sometimes unable to achieve the desired refractive outcome. In these cases, Dr. Hill said that it is generally better to exchange the incorrect IOL for the correct one, for any type of IOL. º/…ˆÃ ˆÃ ˜œÌ `ˆvwVՏÌ] iëiVˆ>Þ if the surgery was done recently,” he explained. “If the refractive miss is small, LASIK would certainly be one option. However, ˆv ̅i ÀivÀ>V̈Ûi “ˆÃà ˆÃ È}˜ˆwV>˜Ì] LASIK may induce higher order aberrations, with a loss of contrast at larger pupil sizes. Surgeons who elect this option are most likely not comfortable with a lens exchange.” For Dr. Koch, the decision depends on the surgeon’s comfort level and the situation. “I perform PCRIs when the spherical equivalent is within 0.25 D of plano,” he wrote. “For myopia down to >ÀœÕ˜` q£°x >˜`…Þ«iÀœ«ˆ> up to 1 D, I usually go with LASIK or PRK. IOL exchange is reserved for greater amounts of ametropia. However, there can be mitigating factors, e.g., the cornea might not be a healthy substrate for excimer laser treatment. For residual astigmatism after implanting a toric IOL, I will rotate the IOL in the lane on day 1 if it is misaligned, and later on manage residual refractive errors with rotation, exchange, occasionally PRK or LASIK, or, quite often, relaxing incisions to eliminate small but symptomatic amounts of astigmatism.” Dr. Koch recognized that these techniques can be challenging and prevent some ophthalmologists from using advanced technology IOLs. “Not all of us have been trained or have a lot of experience with these techniques. Partnering with a colleague who can assist in managing these problems can be reassuring to the ophthalmologist and facilitate optimal patient care.” They may be a challenge, but Dr. Raviv said that “enhancements are a critical part of a refractive cataract surgery practice’s success. If the surgeon can’t offer them, they will face unhappy patients.” According to Dr. Raviv, zonular or capsular compromise make a corneal approach favorable while IOL exchange is better for high “Þœ«ˆV «œÃ̇ Ƃ- iÞiÃ] iÞià with forme fruste keratoconus, >˜` «>̈i˜Ìà `ˆÃÃ>̈Ãwi` ܈̅̅iˆÀ outcomes due to IOL effects such as glare and halo. Both corneal refractive procedures and IOL exchange are thus “critical in a surgeon’s armamentarium,” he said—rounding out and ensuring a successful refractive cataract practice. EWAP References 1. Kane JX, et al. Accuracy of 3 new methods for intraocular lens power selection. J Cataract Refract Surg. Óä£ÇÆ{Î\ÎÎÎqÎΙ° Ó° ,œLiÀÌà /6] iÌ >° œ“«>ÀˆÃœ˜ œv ˆ‡ radial basis function, Barrett Universal and current third generation formulas for the calculation of intraocular lens power during cataract surgery. Clin Exp Ophthalmol. Óä£nÆ{È\Ó{äqÓ{È° 3. Leon P, et al. Correction of low corneal astigmatism in cataract surgery. Int J Ophthalmol. Óä£xÆn\Ç£™qÓ{° 4. Lee J, et al. Comparison of toric vœ`>Li ˆÀˆÃ‡wÝ>Ìi` «…>ŽˆV ˆ˜ÌÀ>œVՏ>À lens implantation and limbal relaxing ˆ˜VˆÃˆœ˜Ã vœÀ “œ`iÀ>Ìi‡Ìœ‡…ˆ}… myopic astigmatism. Yonsei Med J. Óä£ÈÆxÇ\£{Çxqn£° Editors’ note: Dr. Hill is the Medical Director of East Valley Ophthalmology, /GUC #TK\QPC CPF JCU ƂPCPEKCN KPVGTGUVU with Haag-Streit. Dr. Koch is professor and Allen, Mosbacher, and Law Chair in Ophthalmology at the Cullen Eye Institute, Baylor College of Medicine, Houston, and has interests in Alcon, Johnson & Johnson Vision, and Carl Zeiss Meditec. Dr. Raviv is associate clinical professor of ophthalmology at VJG 0GY ;QTM '[G 'CT +PƂTOCT[ QH Mount Sinai, Icahn School of Medicine at Mount Sinai, New York, and has interests in Johnson & Johnson Vision. ADVERTISER LISTING Alcon *>}i Ó] {x‡xÓ www.alcon.com Feather Page 19 www.feather.co.jp/en Glaukos Page 24, 25 www.glaukos.com Johnson & Johnson Vision *>}i x] ÎӇÎx] Èn www.jjvision.com Oculus Page 9 ÜÜÜ°VœÀ˜i>‡ biomechanics.com VSY Biotechnology Page 31 www.vsybiotechnology. com ASCRS *>}i Èä www.ascrs.org APACRS Page 7, 23, 25, 31 39, 54, xÈ] È{] ÈÇ www.apacrs.org