Eyeworld

65 EW FEATURE Editors' note: Drs. Geggel and Negishi have no financial interests related to their comments. Dr. Haigis has finan- cial interests with Carl Zeiss Meditec. In comparison, Wolfgang Haigis, PhD, University Eye Hospital, Wurzburg, Germany, said his use of the Haigis-L formula for the IOLMaster (Carl Zeiss Meditec, Jena, Germany) provides refractive outcomes within 0.5 D of target about 55% of the time. Addressing surprise outcomes Dr. Haigis said that in cases of a surprise error after implantation, he also uses the Haigis-L formula to de- termine the correct power for an IOL exchange after having rechecked all measurement data of the patient. Dr. Negishi does not use any specific formula to determine the correct power for IOL exchange and instead usually calculates the correct power based on the power of the implanted IOL, its target refraction, and the postoperative refractive error. "I use the original calculation sheet and estimate the correct power using the difference between postop refractive error and the target refrac- tion," Dr. Negishi said. For example, if the power of the implanted IOL was +15.0 D, the preop estimated target refraction was –1.11 D, and the postop subjec- tive refraction was +0.02 D, the IOL power calculation error was +1.13 D (hyperopic shift) in subjective refraction. The IOL power for IOL exchange is calculated to be +16.5 D on the basis of the corrected estimat- ed refraction in the primary calcula- tion sheet (Figure 1). Although Dr. Geggel has not had to replace any IOLs because of power miscalculations, he suggest- ed surgeons of patients who had postoperative hyperopia multiply the amount of hyperopia by 1.5 to determine the number of diopters to add to the replacement IOL. "That's how we handle overcorrections or undercorrections on anyone, whether they've had previous refractive surgery or not," Dr. Geggel said. EW References 1. Geggel, HS. Intraocular lens power adjust- ment after myopic excimer laser surgery: validation studies for Geggel ratio and consen- sus group. Cornea 2013;32:1009–1014. 2. Saiki M, Negishi K, Kato N, Ogino R, Arai H, Toda I, Dogru M, Tsubota K. Modified double-K method for intraocular lens power calculation after excimer laser corneal refractive surgery. J Cataract Refract Surg. 2013;39(4):556–62. The specialists in single-use. www.malosa.com • LASIK / LASEK / ReLEx / PRK • Phaco • Oculoplastics • IVT • Strabismus • Sub-Tenons ... "Malosa's single-use instruments and procedure packs provide optimal patient safety and brand new, flawless instruments for every eye." Prof. Dan Z Reinstein, MD MA(Cantab) FRCSC DABO FRCOphth FEBO - The London Vision Clinic • Brand new instruments, every time. • Zero cross-contamination risk. • Increased patient throughput. The specialists in single-use. View our online brochure. Complete range of Instruments and Procedure Packs for all Ophthalmic specialties. Over 350 Instruments & 400 Packs for all specialties. ASCRS BOOTH 2939 Contact information Geggel: ophhsg@vmmc.org Negishi: fwic7788@mb.infoweb.ne.jp Haigis: wh@ocucalc.de February 2015 IOL calculations

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