EyeWorld Asia-Pacific December 2019 Issue

EWAP DECEMBER 2019 41 REFRACTIVE Dr. Shammas: There are different ways to do that. Some biometers will allow you to enter the power of the IOL used and the spherical equivalent œv ̅i w˜> ÀivÀ>V̈œ˜ >˜` ˆÌ will continuously optimize the constants being used. An easy way to do this optimization is to collect at least 50 cases (surgeons can start with 20 cases and update later). 9œÕ ̅i˜ Vœ“«>Ài ̅i w˜> refraction to the one predicted by the formula. You subtract the predicted refraction from the obtained refraction and average all these differences. If the average difference is a negative value, that means that the surgeon is using a higher power IOL than what is required and he/she should decrease the A constant by the (average difference x 1.35). If the average difference is a positive value, then the A constant has to be increased by (the average difference x 1.35). Dr. Holladay: The optimization (or personalization) is performed for each surgeon, each IOL, and i>V…«ÀœVi`ÕÀi vœÀ > ëiVˆwV IOL. For example, you may have surgeon1, IOL1, and manual and femto as procedures. The personalized lens constants for manual and femto are usually different. Another common «ÀœVi`ÕÀi ˆÃ «œÃ̇ÀivÀ>V̈Ûi° This keeps these cases separate for analysis. Do you have any tips to improve the accuracy and reliability of data collection for outcome analysis and clinical TGUGCTEJ!| Dr. Shammas: Data collection for outcome purposes cannot be indiscriminate. In other words, you cannot include all surgeries. My personal opinion is to include the cases that achieve a stable postop refraction with a corrected visual acuity of 20/40 or better. Do not include eyes ܈̅Vœ‡“œÀLˆ`ˆÌˆià ÃÕV…>à macular degeneration, advanced glaucoma, or corneal scarring. Diabetics present a challenge ȘVi ̅i ÀivÀ>V̈œ˜ yÕVÌÕ>Ìià ˆv the diabetes is out of control. Eliminate any cases with advanced diabetic retinopathy. Dr. Holladay: Simply entering the surgical and postoperative data is all you need, but you must have a system setup to do this. As we move forward, the Holladay IOL Consultant Software will obtain this information directly from the electronic medical record (EMR). The Software already imports directly from Optical Biometers (IOLMaster, LenStar, …) avoiding data entry errors, but integrating with the scores of EMRs is a monumental task. How do you incorporate clinical research into your practice without compromising ENKPKECN ƃQY! Dr. Shammas: I personally w˜` Vˆ˜ˆV> ÀiÃi>ÀV…Ìœ Li a challenging part of my professional life. As a busy ophthalmologist, I rarely have time to do any research during clinic hours. I have always taken a half day per week to teach or to work on my research projects. Delegating data collection to medical assistants is not a good idea. They do not understand the importance of data accuracy, for example, separating monofocal from multifocal IOLs or transcribing the astigmatism in negative or positive values. A lot of the data analysis is done by myself at home during the evening hours and the weekends. In the past few years, this process has been facilitated by having our EMR data in the cloud, which I can access from my home computer. Dr. Holladay: It takes time and personnel to enter the data for now, and that costs money. However, patients Ü>˜Ì ̜ Li ëiVÌ>Vi‡vÀii and determining your PLC improves outcomes. This is not the only factor; you must have monocular and binocular screening in place to identify patients preoperatively who are at the highest risk for having a refractive surprise. Monocular screening requires a standard deviation of the keratometry less than 0.20 D (0.030 mm œÀ Îä –“® >˜` > È}˜>‡Ìœ‡ noise ratio of the axial length greater than 2.0. Binocular screening requires the axial length difference to be less than 0.3 mm between eyes and the keratometry and recommended IOL power for > ëiVˆwV Ì>À}iÌ Li iÃà ̅>˜ 1.0 D difference between eyes. EWAP Reference 1. Hayashi K, et al. Changes in corneal astigmatism during 20 years after cataract surgery. J Cataract Refract Sur }° Óä£ÇÆ{Î\È£xqÓ£° Editors’ note: Dr. Holladay is clinical professor of ophthalmology, Baylor College of Medicine, Houston, and has interests in Holladay Consulting Inc. Dr. Shammas is clinical professor of ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles. Shammas post-LASIK formulas are licensed to optical biometers and ultrasound units.