Eyeworld

I AUGUST 2019 | EYEWORLD | 39 CATARACT SURGERY POST-LVC halfway between the two, but ORA plays a lesser role in the decision-making process. This is especially true in circumstances where he is uncertain whether the patient is fixating prop- erly on the target. He also noted that ORA is most helpful for spherical power and cylinder axis; however, topography is the best predictor for cylindrical power. For IOL selection, Dr. Clinch stratifies his post-myopic and post-hyperopic LASIK patients into different categories. Post-myopic LASIK patients are more likely to have smooth optical zones and positive spherical aberration. This makes diffractive IOL options an excellent option. Even for patients who were successful with monovision, he prefers bilateral diffrac- tive IOLs. The result will be binocular distance function that improves depth perception as well as a greater range of intermediate to near vision. Negative spherical aberration is very common in post-hyperopic LASIK patients as well as more irregularity in the optical treatment zone. Dr. Clinch is less likely to use diffractive Considering IOLs Refractive surgery changes the anatomy of the eye, meaning it no longer fits the assump- tions made in many IOL formulas, Dr. Kugler said. Post-refractive IOL calculation formulas attempt to correct those assumptions by making their own set of assumptions, which may or may not be accurate. For this reason, Dr. Kugler said he finds ORA (Alcon) helpful for some post-refractive patients. Dr. Williamson said he relies on ORA, also using the SRK/T and Barrett True K formulas. Dr. Williamson said entering his post-refractive cataract surgery outcomes into ORA refined his results. He also likes that ORA includes the anterior and posterior cornea in its waveform. Dr. Williamson said if a patient has stable keratometry and limited dry eye and higher order aberrations, he would consider a presby- opia-correcting lens. He mostly uses the Sym- fony extended depth of focus lens (Johnson & Johnson Vision). Dr. Clinch uses the Barrett formula and ORA. If there is a small discrepancy, he'll go About the doctors Thomas Clinch, MD Eye Doctors of Washington Washington, D.C. Lance Kugler, MD Kugler Vision Assistant professor Stanley M. Truhlsen Eye Institute University of Nebraska Medical Center Omaha, Nebraska Kevin Waltz, MD President Ophthalmic Research Consultants Indianapolis Blake Williamson, MD Williamson Eye Center Baton Rouge, Louisiana continued on page 40 Dr. Kugler uses iTrace, along with other technologies, to provide information about a post-refractive surgery patient's lens density, light scatter, and visual quality. Source: Lance Kugler, MD

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