EyeWorld Asia-Pacific March 2021 Issue

32 EWAP MAR C H 2021 REFRACTIVE Do Hyung Lee, MD, PhD Professor In Kwon Chung, MD Instructor Ilsan Paik Hospital, Inje University 2240 Daewhadong, Ilsan, Koyang, Gyunggyido, South Korea eyedr0823@hotmail.com ASIA-PACIFIC PERSPECTIVES N owadays, as cataract surgery is regarded as a refractive surgery, managing astigmatism tends to be essential in that it improves both visual acuity and quality. Among the various methods for correcting astigmatism, using corneal laser refractive surgery before or after cataract surgery is an optimal method. However, not all hospitals can afford an expensive excimer laser system. Furthermore, there is another issue of potential complications with LASIK or LASEK surgery. Although limbal relaxing incision (LRI) is another option, we experience poor predictability despite nomograms after surgery as well as patients complaining about their poor visual quality. Furthermore, we often underestimate the biomechanical changes after corneal surgery that ultimately result in poor visual acuity due to the increased cornea higher-order aberrations (HOAs). Among the various methods to manage astigmatism, we prefer to use toric IOLs in patients with astigmatism of 1.50 D or higher, referring to the manifest refraction, topography, and aberrometer for examination. Interesting findings were observed in our recent investigations concerning corneal astigmatism, HOAs, and irregularities in patients prior to cataract surgery. Regardless of the degree of astigmatism, 20% of patients had corneal irregularities affecting the quality of vision after surgery. In other words, many candidates for cataract surgery may have components of regular and irregular astigmatism. In terms of correcting astigmatism, not only regular astigmatism but also irregular astigmatism should be evaluated for better postoperative surgical results (presented in Symposium during the 122 nd KOS meeting, 2019, Seoul, South Korea). When we looked at the case of a 55-year-old female patient with cornea opacity due to recurrent herpes keratitis, her manifest refraction was –1.00 D astigmatism, but corneal astigmatism using aberrometer was –5.25 D and 0.612 cornea HOA. We decided to perform cataract surgery with toric IOL implantation. As a result, she could see 16/20 without spectacles after surgery (Figure 1). The reason for this good result is that while corneal HOA did not change, total ocular aberration decreased significantly. In our experience, implantation of toric IOLs is effective in well selective cases combined cataract and corneal irregular astigmatism. It is important to analyze how much astigmatism is regular or irregular, and to determine whether it is effective to implant toric IOLs in patients with regular and irregular astigmatism. Although astigmatic correction using toric IOLs have many limitations, it would certainly be better to try astigmatism manage as much as possible than without correcting it. Editors’ note: The authors declared no relevant financial interests. Figure 1. Pre- and postop in a case with corneal opacities due to herpes keratitis. Source: Do Hyung Lee, MD F/55 Cornea opacity d/t Herpes (OD) Pre op MR(OD) : 20/100 x +2.00 -1.00 Ax 90 Corneal Astig (4mm) : -5.25 Ax 109 (Wavefront) Corneal HOA (4mm) : 0.612 Total Ocular HOA(OD) : 0.513 Case § Toric IOL (Tecnis Toric, ZCT 375, J&J, USA) Post-op MR(OD) : 16/20 x PL Corneal Astig (4mm) : -4.00 Ax 65 (Wavefront) Corneal HOA (4mm) : 0.610 Total Ocular HOA(OD) : 0.352 If the patient is contraindicated for the Light Adjustable Lens— if they have poor dilation, concerns with compliance of the UV blocking glasses required until treatment is locked in, etc.—toric lenses remain a fantastic option, Dr. Swan said. Dr. Lee said he’s had good results with toric lenses in patients with prior laser vision correction, even if their cornea isn’t completely regular. However, he mentions preoperatively that toric IOLs are not labeled to correct irregular astigmatism. “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 topography 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 Adjustable 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