REFRACTIVE 20 EWAP DECEMBER 2022 Overall, Dr. Chang said that aligning to the SF-CSCLR or considering preoperative chord kappa may be “splitting hairs,” which is why he doesn’t typically place too much emphasis it. “We defined it, and my goal is to help industry put it in their devices, so surgeons don’t have to think through the intricacies of the topic,” he said. “I personally still center on the SF-CSCLR as best as I can, but I know that decentration is only one of many possible causes of residual astigmatism.” Douglas Koch, MD, who defined angle kappa as the distance between the corneal light reflex when the patient is coaxially fixating on a light source and the center of the entrance of the pupil, said that it has “yet to be proven” whether angle kappa is an important issue. “That said, Dr. Chang’s and Dr. Waring’s article was hugely helpful in defining a measurement that we could use to study this topic,” he said. “However, I’m not sure that angle kappa is as important as we once thought that it was,” Dr. Koch said. “I think it is important for people to continue to look at it, and if I see a large angle kappa, I discuss it with patients and tell them that we don’t know, and it might be an issue. But I am not aware of any studies that convincingly correlate angle kappa and outcomes, and I’ve yet to see visual problems from putting a presbyopia-correcting lens in these patients.” EWAP References 1. Chang DH, Waring GO. The subjectfixated coaxially sighted corneal light reflex: a clinical marker for centration of refractive treatments and devices. Am J Ophthalmol. 2014;158:863–874. 2. Prakash G, et al. Predictive factor and kappa angle analysis for visual satisfactions in patients with multifocal IOL implantation. Eye (Lond). 2011;25:1187–1193. 3. Sandoval HP, et al. The effects of angle kappa on clinical results and patient-reported outcomes after implantation of a trifocal intraocular lens. Clin Ophthalmol. 2022;16:1321–1329. 4. Fu Y, et al. Influence of angle kappa and angle alpha on visual quality after implantation of multifocal intraocular lenses. J Cataract Refract Surg. 2019;45:1258–1264. Editors’ note: Dr. Chang is Cataract and Refractive Surgeon at Empire Eye and Laser Center, Bakersfield, California, and has interests with Carl Zeiss Meditec. Dr. Koch practices at the Department of Ophthalmology, Cullen Eye Institute, Baylor College of Medicine, Houston, Texas, and disclosed no relevant financial interests.
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