Eyeworld

I WHAT OPHTHALMOLOGISTS SHOULD BE DOING TODAY N FOCUS 48 | EYEWORLD | OCTOBER 2019 Contact information Hill: hill@doctor-hill.com Koch: dkoch@bcm.edu Raviv: tal.raviv.md@gmail.com 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 er- rors 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 ophthal- mologists 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 myo- pic post-LASIK eyes, eyes with forme fruste keratoconus, and patients dissatisfied with their 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. [Bausch + Lomb]) or 1.50 D (AcrySof [Al- con] or Tecnis Toric [Johnson & Johnson Vision]), which trans- lates 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 the 180-degree axis and more relaxing incisions at the 90-degree axis or oblique axis." Dr. Koch again made allowance for individ- ual surgeon experience, saying that the choice between relaxing incisions and toric IOLs "de- pends on one's comfort level with both technol- ogies. In my practice, I perform relaxing inci- sions if there is –0.3–0.5 D of against-the-rule astigmatism, 0.3–0.7 D of oblique astigmatism (depending in part on the orientation of the astigmatism versus my incision location), and 0.8–1.5 D of with-the-rule astigmatism. Any- thing above that is treated with a toric IOL." Enhancements Despite surgeons' best efforts, they are some- times 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. "This is not difficult, especially if the sur- gery was done recently," he explained. "If the refractive miss is small, LASIK would certainly be one option. However, if the refractive miss is significant, LASIK may induce higher order ab- errations, 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 equiva- lent is within 0.25 D of plano," he said. "For myopia down to around –1.5 and hyperopia 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 continued from page 47 References 1. Kane JX, et al. Accuracy of 3 new methods for intraocular lens power selection. J Cataract Refract Surg. 2017;43:333–339. 2. Roberts TV, et al. Comparison of Hill-radial basis function, Barrett Universal and current third gener- ation formulas for the calculation of intraocular lens power during cataract surgery. Clin Exp Oph- thalmol. 2018;46:240–246. 3. Leon P, et al. Correction of low corneal astigmatism in cat- aract surgery. Int J Ophthalmol. 2015;8:719–24. 4. Lee J, et al. Comparison of toric foldable iris-fixated phakic intraocular lens implantation and limbal relaxing incisions for moderate-to-high myopic astigmatism. Yonsei Med J. 2016;57:1475–81. Relevant financial interests Hill: Haag-Streit Koch: Alcon, Johnson & Johnson Vision, Carl Zeiss Meditec Raviv: Johnson & Johnson Vision "Enhancements are a critical part of a refractive cataract surgery practice's success." —Tal Raviv, MD

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