Eyeworld

78 | EYEWORLD | DECEMBER 2020 R EFRACTIVE Considering irregular astigmatism Ocular surface conditions causing irregular astigmatism, such as ABMD, Salzmann's nodu- lar degeneration, and pterygium, are very treat- able. Dr. Swan said he'll treat these conditions "Post-RK toric results are pretty good, but measuring those corneas is even more difficult than post-LASIK eyes. I will occasionally do an LRI in someone who had LASIK or PRK if the to- pography looks good and the cylinder is too low for a toric. I think the best option for essentially all post-refractive patients is the Light Adjust- able Lens," Dr. Lee said, pointing out that the Light Adjustable Lens needs at least 0.75 D of cylinder to correct, otherwise it's only correcting spherical adjustments. Dr. Ristvedt also called the Light Adjustable Lens a "game changer" for both post-corneal refractive surgery patients and those with naive corneas. "By having an IOL where you can correct the lens itself and you don't have to fine tune the cornea, it gives me more confidence that we can hit the refractive target despite lens positioning, corneal healing, and preoperative measurement variations," she said. Dr. Wiley emphasized the importance of taking the patient's perception of their current astigmatism into account and setting appropri- ate postop expectations. He said it's important to diagnose all areas of astigmatism preop and relate to the patient. Intraoperative aberrometry can be helpful as well. "I tell patients even though you might not be showing astigmatism now, you don't know what the final astigmatism is going to be until after the cataract is removed, after I make my incisions for cataract surgery and the eye is in a new state. If you want to see well without glass- es, we need to manage your astigmatism, and it may be something that appears during surgery or even after surgery, but we should be prepared for that," he said. In terms of the different options for astig- matic correction in cataract surgery, Dr. Wiley talks to his patients in percentages. "I'll tell them that with basic technology we can often reduce the prescription somewhere between 50–100%; even with basic we can get lucky and hit 100%, and that's great. Advanced technologies, like a toric lens, can reduce it to 90–100%, better than basic and quite good but even that means some margin of error. If you want 98–100%, I'll say the Light Adjustable Lens," Dr. Wiley said. continued on page 80 continued from page 76 Treating low corneal astigmatism with femto Gary Wortz, MD, et al. recently published a paper in Clinical Ophthalmology that shared real-world outcomes of treating low corneal astigmatism of less than 1 D with a novel formula for femtosecond laser arcuate inci- sions. The outcomes of this were compared to basic cataract surgery without surgical management for low levels of astigmatism. According to the paper, the Wortz-Gupta Formula calculated arcuate parameters for 224 patients with less than 1 D of astigma- tism; the Barrett Universal II formula was used for IOL calculations. Average preoper- ative cylinder was similar in the femtosec- ond group vs. the conventional cataract surgery group (0.61 D [n=124] and 0.57 D [n=100], respectively). More patients had more than 0.5 D of astigmatism in the fem- tosecond group compared to the conven- tional group. The investigators found that the mean postop refractive astigmatism was significantly higher in the convention- al cataract surgery group. More patients achieved UCDVA 20/20 or better in the fem- tosecond group (62%) vs. the conventional group (48%). The study authors concluded that "[u]sing femtosecond laser for arcuate incisions in combination with a novel nomo- gram can provide excellent anatomic and refractive outcomes in patients with lower levels of preoperative astigmatism at the time of cataract surgery." Reference Wortz G, et al. Outcomes of femtosecond laser arcuate incisions in the treatment of low corneal astigmatism. Clin Ophthalmol. 2020;14:2229–2236. Relevant disclosures Berdahl: Alcon, Bausch + Lomb, Johnson & Johnson Vision, RxSight Lee: Carl Zeiss Meditec Ristvedt: None Swan: None Wiley: Alcon, Johnson & Johnson Vision, RxSight, Carl Zeiss Meditec

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