AUG 2019

EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.

Issue link: https://digital.eyeworld.org/i/1148281

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Page 26 of 82

24 | EYEWORLD | AUGUST 2019 ATARACT C by Rich Daly EyeWorld Contributing Writer Contact information Gupta: preeyakgupta@gmail.com Patterson: michaelp@ecotn.com Raviv: tal.raviv.md@gmail.com Yeu: eyeulin@gmail.com place a toric IOL for 0.3 D of keratometric against-the-rule cylinder. "The highest powers of monofocal IOLs treat about 4.0 D of corneal cylinder, but I'll use them in higher amounts, such as post-PK, explaining to the patient that we are debulking their astigmatism and cannot fully eliminate it with an IOL alone," Dr. Raviv said. Preop preparation Dr. Yeu said online calculators that incorporate the Barrett Toric algorithm for toric IOLs are extremely accurate. Dr. Yeu uses Veracity Surgi- cal (Carl Zeiss Meditec) for her IOL planning, which incorporates the Barrett Toric Calculator and the effects of posterior corneal astigma- tism, effective lens position, and likely IOL tilt into the toric IOL recommendation. The Alcon Toric Calculator utilizes the Barrett Toric algorithm, and the Johnson & Johnson Vision A n increasing number of patients are presenting for cataract surgery evaluation with the expectation that modern refractive surgery will de- crease their dependence on glasses. Surgeons say that has increased the importance of treating astigmatism to provide excellent uncorrected visual results. Tal Raviv, MD, noted that in studies com- paring corneal relaxing incisions to toric IOLs, toric IOLs have consistently been more accurate and reliable. The three monofocal toric IOLs available to U.S. surgeons are the AcrySof IQ Toric (Alcon), Tecnis Toric (Johnson & Johnson Vision), and enVista Toric (Bausch + Lomb). The three pres- byopic toric options are the Symfony Toric IOL (Johnson & Johnson Vision), Trulign (Bausch + Lomb), and the ReSTOR Toric (Alcon). The lowest toric IOL astigmatic power available to U.S. surgeons is the enVista Toric IOL, which corrects down to 0.7–0.8 D of total corneal astigmatism, said Elizabeth Yeu, MD. "This is great because now I can use a toric IOL for those with about 1.0 D of anterior with-the-rule corneal astigmatism and about 0.5 D anterior against-the-rule astigmatism," Dr. Yeu said. Lens uses The minimal amount of astigmatism Michael Patterson, DO, would correct with an IOL is 0.75 D, while the maximum is 4–5 D. Preeya Gupta, MD, said the threshold for toric IOL use depends on whether the astigma- tism is with-the-rule or against-the-rule. "With-the-rule astigmatism is often correct- ed with a toric intraocular lens when it is greater than 1.5 D," Dr. Gupta said. "Against-the-rule astigmatism, however, is corrected with a toric intraocular lens when there is greater than 0.9 D of astigmatism." Dr. Raviv noted that when a surgeon takes into account posterior surgical astigmatism and targets about 0.25 D of with-the-rule astig- matism (to allow for future with-the-rule to against-the-rule drift), it is not uncommon to DEVICE FOCUS Getting the most out of toric lenses Image of against-the-rule astigmatism in which the total corneal astigmatism of 0.84 D is higher than the anterior corneal astigmatism of 0.63 D and warrants a toric IOL over a relaxing incision Source: Tal Raviv, MD About the doctors Preeya Gupta, MD Associate professor of ophthalmology Duke University Eye Center Durham, North Carolina Michael Patterson, DO Eye Centers of Tennessee Crossville, Tennessee Tal Raviv, MD Associate clinical professor of ophthalmology Icahn School of Medicine at Mount Sinai New York Elizabeth Yeu, MD Assistant professor of ophthalmology Eastern Virginia Medical School Virginia Eye Consultants Norfolk, Virginia continued on page 26

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