EyeWorld India December 2021 Issue

The Importance of Precise Toric Correction for PC IOLs Ronald Yeoh, MD, Singapore Looking at global data from 2016, less than 10% of IOL implantations utilize toric IOLs. However, Dr. Yeoh stat- ed that his personal usage of toric IOLs has been around 40% since 2015. “With the increased ef cacy and rec- ognition of the precision of the Barrett toric calculator, this went up to 75% in 2017,” says Dr. Yeoh. Last year, Dr. Yeoh was implanting 80% toric IOLs in his patients. It is important, though, when implanting toric IOLs to ob- serve the incidence of astig- matism in cataract patients. “When we are doing presby- opia-correcting IOLs, we are aiming for spectacle freedom, and hence image-degrading astigmatism really has to be eradicated,” says Ronald Yeoh, MD. In fact, in PC IOLs, astigmatism degrades image quality much more so than in monofocal IOLs. Recent data has shown that 65% of patients achieve 1 diopter or less of corneal cylinder, imply- ing that only 35% of cataract patients require a toric IOL. This statistic con icts with Dr. Yeoh’s use of toric IOLs in up to 80% of his patients. Dr. Yeoh explains that tradi- tional thinking implies that toric calculations are done only for patients with more than 1 diopter of astigmatism, and thus toric IOLs are only used for these patients. “This is awed thinking,” says Dr. Yeoh, “because it disregards posterior corneal astigmatism (PCA).” K values do not equal total corneal astigmatism, and against-the-rule (ATR) astigmatism is hidden in the posterior cornea which is not actually measured by anteri- or keratometry. To apply this theory in practice, posterior corneal astigmatism is built into the Barrett Toric Calcula- tor, and the Integrated K cal- culator optimizes three sets of K data. The values that result from the calculator allow for improved residual astigma- tism outcomes. While Dr. Graham Barrett is particular about correcting astigmatism at the time of cataract surgery for monofo- cal IOLs and monovision, Dr. Yeoh believes that we should be even more particular about correcting astigmatism when using PC IOLs. Doing toric calculations in all patients us- ing the Barrett Toric Calculator is key when aiming for zero astigmatism in cataract pa- tients. Interestingly, Dr. Yeoh presented data showing that, out of more than 4 million total clicks to all Barrett IOL Calculators, only about 28% of those clicks were directed to the Barrett Toric Calculator. The majority of clicks (66%) went to the Barrett Universal II Formula, which is used only for the spherical component. “We still have a ways to go to convince people that they should really be doing toric calculators as their rst line rather than the spherical cal- culation,” says Dr. Yeoh. While there are an abundance of IOL options for clinicians to choose from, the most import- ant factors to consider are the patients’ desired outcomes and tailoring IOL implantation to their lifestyle. The interac- tive panel discussion from this webinar provided an oppor- tunity for key clinicians in the cataract and refractive arena to share their ideas on which IOLs provide bene t to which types of patients. “We’re all looking for better ways to funnel patients the right way,” says Dr. Ahmed. Less than 65% of patients have 1 diopter or less of corneal cylinder. “ In picking the right presbyopia-correcting (PC) IOL, surgeons should aim to match their patients’ expectations while understanding that there is always some tradeoff when manipulating light. ” Dr. Ike Ahmed Copyright 2021 APACRS. All rights reserved. The views expressed here do not necessarily reflect those of the editor, editorial board, or publisher, and in no way imply endorsement by EyeWorld, Asia-Pacific or APACRS. All other trademarks are the intellectual property of their respective owners. © Johnson & Johnson Surgical Vision, Inc. 2021 PP2021CT6299 “ Doing toric calculations in all patients using the Barrett Toric Calculator is key when aiming for zero astigmatism in cataract patients. ” Dr. Dr. Ronald Yeoh