Eyeworld

109 EW INTERNATIONAL October 2017 What do we do with all the dif- ferent options? The implementation of different methods could produce doubts in the surgeon who faces de- cisions that are going to determine the patient's satisfaction, especially when multifocal and toric lenses are being implanted. In my practice, I am looking for consistency not only among the different techniques, but also in between them and the pa- tient's subjective refraction. Finding inconsistencies among the methods or between them and the refraction is an indicator of possible postop- erative "refractive surprise" that is shared with the patient. We are still waiting for the ideal method in accuracy and cost for the calculation of intraocular lenses. As doctors, we can and should al- ways take care of multiple pre- and transoperative details in order to achieve the best possible result with the technology that we have in our hands. EW References 1. Clevenger CE. Clinical prediction versus ultrasound measurement of IOL power. J Am Intraocul Implant Soc. 1978;4:222–4. 2. Rajan MS, et al. Partial coherence laser interferometry vs conventional ultrasound bi- ometry in intraocular lens power calculations. Eye (Lond). 2002;16:552–6. 3. Huang J, et al. Meta-analysis of optical low-coherence reflectometry versus partial coherence interferometry biometry. Sci Rep. 2017;7:43414. 4. Arriola-Villalobos P, et al. Agreement and clinical comparison between a new swept- source optical coherence tomography-based optical biometer and an optical low-coher- ence reflectometry biometer. Eye (Lond). 2017;31:437–442. Editors' note: This article was first published in ALACCSA-R #22, May/ June, pages 8–10 and is included here with permission from ALACCSA. For more information on ALACCSA, go to www.alaccsa.com. Contact information Viteri: eviteri@humanavision.com by means of optical biometry is 10 times more precise than ultra- sound, it has only produced a 16% higher postoperative accuracy. 2 Minor improvements have been made in the optical low coherence reflectometry systems 3 and swept- source OCT 4 that allow physicians to determine both the lens and the corneal thickness, but still haven't reached clinical significance. In cases of severe cataracts, immersion ul- trasound biometry remains the best technique. Corneal evaluation is the biggest challenge and goes beyond a simple keratometer. Scheimpflug technology allows us to evaluate the transparency of the cornea, as well as the power of the corneal anterior and posterior chambers. Moreover, it provides us guidelines on the asphe- ricity and determining if the patient is a good candidate for implantable multifocal intraocular lenses. The next step is to process this information with different types of formulas that would be beneficial to one degree or another. Methods like ray tracing or transoperative biom- etry offer logical and theoretical advantages, but the outcomes still do no provide significantly precise results. The Panacea IOL applica- tion (panaceaiolandtoriccalculator. com) allows the surgeon to use only one formula for every eye regard- less of whether it has gone through refractive surgery or suffers from any corneal pathology. The RBF calcula- tor developed by Warren Hill, MD (rbfcalculator.com) uses sophisti- cated statistical analysis to identify patterns that will help classify each eye, optimizing the result in an empirical way. Obviously, not everything depends on technology. Differences between operators, corneal lubri- cation conditions, the astigmatism induced by the surgeon, as well as our limitations trying to find an intraocular toric lens in the correct meridian contribute to making it more difficult to get satisfactory predictability. A F R E S H P E R S P E C T I V E ™ © 2017 Lacrivera, a division of Stephens Instruments. All rights reserved. lacrivera.com ( 855 ) 857-0518 VeraPlug™ FlexFit ™ Use promo code FLEXEW for introductory pricing 2500 Sandersville Rd ■ Lexington KY 40511 USA Refresh your dry eye practice. Introducing the new VeraPlug™ FlexFit,™ a familiar design with the same simple sizing, patient comfort, and retention that you expect. Lacrivera offers a fresh approach to bring greater value to your dry eye practice. Visit us at AAO booth #3744

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