EyeWorld India December 2019 Issue

40 EWAP DECEMBER 2019 REFRACTIVE Contact information Holladay: holladay@docholladay.com Shammas: HShammas@aol.com This article originally appeared in the October 2019 issue of EyeWorld . It has DGGP UNKIJVN[ OQFKƂGF CPF CRRGCTU here with permission from the ASCRS Ophthalmic Services Corp. Y ou’ve performed cataract surgery, implanted your selected IOL, and conducted postop visits. While it might sound like your job is done at this point, if you want to improve your outcomes further, now’s the time to start crunching numbers. EyeWorld reached out to experts H. John Shammas, MD, and Jack Holladay, MD, to get their thoughts about systems for selecting IOLs and managing calculations, following up on refractive outcomes, and tips for conducting clinical research with IOL data. At what point postoperatively do you recommend collecting variables for outcome analysis? What would you say are the most relevant variables VQ EQNNGEV HTQO GCEJ RCVKGPV!| Dr. Shammas: After surgery, we refract the operated eye on day 1 and day 7. These early refractions will ensure that no errors in the IOL calculations have been made, [which] might require immediate intervention. However, the best time to check ̅i w˜> œÕÌVœ“i ˆÃ { ̜ È ÜiiŽÃ after the surgery; this is when we prescribe glasses. If the surgeon or his/her staff want to conduct an outcome analysis, they would record the IOL power and the w˜> ÀivÀ>V̈œ˜° Dr. Holladay: Six months after surgery is ideal for stability in the spherical equivalent refraction as well as the residual astigmatism. Although 3 months is often used, it is too soon for changes in the capsular bag to be complete and axial changes in the IOL are still occurring. FDA clinical trials have visits at 1 day, 1 month, Î “œ˜Ì…Ã] È “œ˜Ì…Ã] >˜` £ Þi>À° /…i ȇ“œ˜Ì…`>Ì> ˆÃ ÕÃÕ>Þ the visit where refraction is used vœÀ >˜>ÞÈð /…iÀi ˆÃ > œ˜}‡ ÌiÀ“ `ÀˆvÌ ˆ˜ >}>ˆ˜Ã̇̅i‡ÀՏi astigmatism of about 0.25 D per decade that is the same for both cataract surgery and controls found by Ken Hayashi, MD, in his article following patients for 20 years. 1 How do you collect your postop outcomes data for later optimization analysis? What systems do you use? Dr. Shammas: You do not need any system. You have to record the power of the IOL used and the spherical equivalent of the w˜> ÀivÀ>V̈œ˜° Dr. Holladay: The Holladay IOL Consultant Software does this automatically when you enter the surgical and postoperative refraction. The optimization excludes outliers that are more than two standard deviations from the mean because they are usually measurement errors and cases with less than 20/50 best corrected vision because the refraction is suspect. The Software does not actually use the personalized lens constant (PLC) until it reaches ÃÌ>̈Ã̈V> È}˜ˆwV>˜Vi] ܅ˆV…ˆÃ usually from 30 to 50 cases. It looks at the data through a “rearview window,” looking at the data that is most recent wÀÃÌ >˜` }œˆ˜} L>VŽ…ˆÃ̜ÀˆV>Þ ՘̈ ÃÌ>̈Ã̈V> È}˜ˆwV>˜Vi is reached. This keeps the PLC “fresh” in case the surgeon makes changes in his surgical technique that may unknowingly affect the PLC. What is your process of optimization of surgical outcomes derived from your collection of data? What is the process of how you go from a collection of postop outcomes data to optimization of your future IOL calculations? Crunching numbers for IOL optimization by Liz Hillman EyeWorld Senior Staff Writer