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Astigmatism management for today's patient: Technologies and techniques that take your practice to the next level Excellent outcomes are only as stable as the toric IOL you choose By John Berdahl, MD percentage of lenses with orientation 5° or more from intended was 0.89% overall. However, the percentage varied significantly between specific toric IOL brands. Specifically, the relative percentage of Tecnis Toric IOLs that were 5° or more from their intended rota- tion (1.86% by estimated market usage, n = 1,953) was significantly higher than the percentage of AcrySof IQ Toric IOLs (0.75% by estimated market usage, n = 3,556; p<0.01 for the comparison). Our study also found that the Tecnis Toric IOL ap- pears more likely to be misoriented in a counter- clockwise direction than in a clockwise direction (65% counterclockwise vs. 35% clockwise, n = 1,953, p<0.01). In contrast, the other lenses tested — in- cluding the AcrySof IQ Toric IOLs — showed no rotation- al bias. There are two important features to consider when choosing a toric IOL: rota- tional stability and good op- tics. We have learned that lenses do rotate sometimes and that our preoperative measurements aren't al- ways a great representation of how much astigmatism the eye truly has. Toric lenses do a great job of treating the astigmatism, but having a consistent and reliable process for measur- ing preoperatively, poten- tially measuring intraop- eratively with aberrometry to confirm those measure- ments, and then placing a good rotationally stable lens is going to give us the highest likelihood of neu- tralizing the astigmatism. It may be a little bit of over- kill, but I get three sourc- es of Ks prior to cataract surgery on every patient: topography, autorefractor, and optical biometry. Intra- operatively, I use aberrom- etry, and this often changes my IOL power because it's taking a measurement after an incision has been creat- ed and taking into account posterior corneal curvature. Using this preoperative and intraoperative approach, we are achieving very good results, approaching 85% to 90% of patients within 0.5 D of residual astigma- tism, but that means there are still patients who have residual astigmatism, and we need to have a plan to correct that. That plan could include an excimer laser enhancement, an IOL rotation using something like astigmatismfix.com to calculate the new axis, or an IOL exchange. As toric multifocals become available, correcting toricity is going to be even more important and less forgiv- ing, and we need to do a really good job correcting astigmatism for our pa- tients to achieve their best outcomes. n Reference 1. Potvin R, Kramer BA, Hardten DR, Berdahl JP. Toric intraocular lens orientation and residual refractive astigmatism: an analysis. Clin Ophthalmol. 2016;10:1829-1836. E ven low levels of astig- matism need to be addressed during cat- aract surgery to get an optimal postoperative result. I typically evaluate whether to correct astigmatism starting at 0.5 D. At lower levels of cylinder, people can still see well, but at about 0.5 D, it becomes visually significant, especially in combination with multifocality. Toric IOLs are a good choice for managing astigmatism, and there have been huge improvements in these lenses in recent years. How- ever, for a lens to success- fully correct astigmatism, it must be stable inside the eye. The AcrySof IQ Toric platform is a great option for astigmatism correction, particularly because of its rotational stability. To examine rotational sta- bility, my colleagues and I recently analyzed IOL orien- tation data from an online toric back-calculator (astig- matismfix.com) to see if differences were apparent by lens type. 1 In this retro- spective review, we looked at astigmatismfix.com toric back-calculations that included IOL identification and intended orientation axis. Of the 12,812 total vali- dated calculation records, 8,229 included the intended orientation and lens identi- fication data. Of the 8,229, 5,674 calculations (69%) involved lenses that were oriented 5° or more from their intended position. Us- ing estimated toric lens us- age data, we found that the

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