ArticleNew algorithm for intraocular lens power calculations after myopic laser in situ keratomileusis based on rotating Scheimpflug camera dataPotvin, Richard OD*; Hill, Warren MD Author Information From Science in Vision (Povin), Akron, New York, and East Valley Ophthalmology (Hill), Mesa, Arizona, USA *Corresponding author: Richard Potvin, OD, Science in Vision, 6197 Dye Road, Akron, New York 14001, USA. E-mail: [email protected] Submitted March 29, 2014; revised May 8, 2014; accepted May 9, 2014. Supported by a research grant from Oculus Optikgeräte GmbH, Wetzlar, Germany, to Science in Vision, Akron, New York, USA. Sarah Y. Makari, OD, is a consultant to Science in Vision who received compensation for assisting in the preparation of this manuscript.Figure: No Caption available.First author: Richard Potvin, OD Science in Vision, Akron, New York, USA Journal of Cataract & Refractive Surgery 41(2):p 339-347, February 2015. | DOI: 10.1016/j.jcrs.2014.05.040 Buy Metrics Abstract Purpose To develop an algorithm to calculate intraocular lens (IOL) power for eyes with previous laser in situ keratomileusis (LASIK) for myopia based on data from a rotating Scheimpflug camera and to compare calculations with those of current formulas. Setting East Valley Ophthalmology, Mesa, Arizona, USA. Design Observational case series. Methods Relevant IOL calculation and postoperative refractive data were obtained for eyes of patients who had previous myopic LASIK and subsequent cataract surgery. Initial screening and correlation analysis identified Pentacam Scheimpflug keratometry (K) values appropriate for use in calculating a “best K” for IOL power calculations in these eyes. Error analysis identified other eye measures to improve results. Final results were compared with results from 9 other calculation methods available on the American Society of Cataract and Refractive Surgery (ASCRS) web site. Results The study obtained data from 101 eyes of 77 patients. More than 200 Scheimpflug K–formula combinations were evaluated for each eye. The true net power in the 4.0 mm zone centered on the corneal apex provided the best adjusted K reading for IOL power calculation in the Shammas no-history formula. The final formula had good outcomes, with 34%, 66%, and 91% of eyes being within ±0.25 diopter (D), ±0.50 D, and ±1.00 D of the refractive target, respectively. These results compare favorably to the best formulas on the ASCRS web site. Conclusions The no-history formula derived using the Scheimpflug device’s true net power in the 4.0 mm zone centered on the corneal apex appears to be an accurate method for determining IOL power after LASIK for myopia. Corroboration with additional data sets is suggested. Financial Disclosure Neither author has a financial or proprietary interest in any material or method mentioned. © 2015 by Lippincott Williams & Wilkins, Inc.
