APACRS 2021 Daily News (Saturday, 31 July 2021)

MasterClass: Mastering Toric IOLs Toric IOLs are “a very powerful tool to reduce the amount of preexisting astigmatism at the time of cataract surgery,” said Tetsuro Oshika, MD, PhD, Japan. On Friday, Dr. Oshika spoke at a MasterClass on “Mastering toric IOLs,” bracketing the course with lectures on “Preoperative considerations and patient selec- tion” and “Complication management and difficult cases.” In his first talk, Dr. Oshika laid down the basics: with-the-rule astigmatism (WTR) is astigmatism with the steepest meridian on the vertical axis and the flattest meridian on the horizontal axis, while against-the-rule (ATR) is the opposite; young eyes tend to have an anterior corneal surface with WTR that shifts to ATR with age, while the posterior corneal surface tends to remain ATR “almost throughout life”; ignoring the posterior surface re- sults in undercorrection of ATR astigmatism and overcorrection of WTR astigmatism, so it is important to use toric calculators that consider the influence of posterior corneal astigmatism, such as the Barrett Toric Calculator. Regarding patient selection, Dr. Oshika said that toric IOLs are indicated in eyes with regular astigmatism, so the presence and degree of irregular astigmatism should be evaluated via corneal topography. He particularly recommended using a Fourier map, which decomposes topography into four components: spherical, regular astigmatism, asymmetry, and higher-order irregularity. If the latter two components are dominant, then the eye is not a good candidate for toric IOL implantation. For implantation, Dr. Oshika emphasized the importance of precise axis marking. He noted that carefully performed manual marking can offer clinically satisfactory results not significantly different from digital systems; however, digital systems improve workflow by eliminating the need for preoperative marking in most cases. “Toric lenses play a key role in improving refractive outcomes,” said Graham Barrett, MD, Australia, and for these lenses, accu- rate prediction of toric cylinder is essential. Dr. Barrett walked through the use of a suite of IOL power calculators he created and has made available via the APACRS website ( apacrs.org) , comprising the Barrett Universal II (BUII), identical to the Barrett Universal II TK (Total Keratometry) avail- able with the IOLMaster700; the Barrett Toric Calculator, similar to BUII but in addition to providing identical spherical power prediction predicts toric cylinder; the Barrett True K and True K Toric calculators which incorporate the option to use measured posterior cornea values; and the Barrett RX formula for deter- mining the best way to manage unexpected outcomes, whether through IOL exchange, piggyback IOL implantation, or toric IOL rotation. The option to use measured posterior cornea values from dif- ferent devices is perhaps the most valuable update to his cal- culators. His K calculator allows the user to enter K-values from EWAP Daily News - 4 In postoperative macular edema, Kelvin Teo, MD, Singa- pore, emphasized the importance of multimodal imaging for differentiating the cause of cystoid macular edema, specifically with fluorescein angiogram. Finally, Caroline Chee, MD, Singapore, ended the session discussing considerations and techniques for cataract surgery after retinal surgery. As vitreoretinal surgery is more common now than ever before, surgeons must consider a comprehensive patient history and perform a thorough examination. Assessment should include whether the pa- tient has glaucoma, examining the posterior segment, and whether the patient has other abnormalities such as nucle- arsclerosis or posterior subcapsular opacity. These consid- erations, along with proper technique, will reward patients with significant visual improvement.