Kevin M. Miller, MD Kolokotrones Professor of Clinical Ophthalmology David Geffen School of Medicine at UCLA

Transcription

1 IOL Power Calculation l in Post-LASIK Eyes Kevin M. Miller, MD Kolokotrones Professor of Clinical Ophthalmology David Geffen School of Medicine at UCLA Jules Stein Eye Institute I have no financial disclosures relevant to this presentation.

2 Consulting Fee: HOYA Surgical Optics; Physical Optics Corporation Fees for Non-CME Services: SLACK Incorporated Contracted Research: Alcon Laboratories, Inc.; Calhoun Vision Disclosures

3 I would like to acknowledge the contribution of Rishabh C. Date, a UCLA medical student, to this study. Acknowledgment

4 To validate the Diehl-Miller equation for achieving emmetropia at the time of cataract surgery in post-lasik eyes and to present a refined equation. The Diehl-Miller equation relates the manifest refractive spherical equivalent (MRSE) change induced dby LASIK to an adjusted target postoperative refractive error to be used in IOL power calculations. Purpose

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6 Target refractive error = (MRSE 018(MRSE Change) (MRSE Change) MRSE = Manifest Refraction Spherical Equivalent Diehl-Miller Polynomial Equation

7 Myopic LASIK MRSE Change Target Induced by Refractive Error LASIK (D) to Achieve Emmetropia (D) Hyperopic LASIK MRSE Change Target Induced by Refractive Error LASIK (D) to Achieve Emmetropia (D) Look Up Tables

8 In a regression analysis, we expect the equation to fit the data from which hit was derived. The issue is how well it predicts the behavior of a set of completely new data? The Issue

9 Preoperative and postoperative refractive and cataract surgery data were collected from the medical records of post-lasik patients who underwent cataract surgery between July 2007 and June Twenty-three th eyes from 18 patients t were evaluated. The Diehl-Miller nomogram was used to target emmetropia in all study eyes. Methods

10 After cataract t surgery, IOL power dt data and postoperative ti refractive information were used to calculate the target refractive error that should have been chosen to achieve emmetropia. The polynomial equation produced by the regression analysis of these data was compared to the equation obtained in the original analysis. Regression analysis of the combined data from the Diehl- Miller study and the current study was used to develop a refined equation, the Diehl-Date-Miller nomogram. Methods

11 Diehl-Miller: Target refractive error = (MRSE Change) (MRSE Change) Dt Date-Miller: Target refractive error = (MRSE 017(MRSE change) (MRSE change) There was no statistically significant difference between the Diehl-Miller and Date-Miller equations. MRSE = Manifest Refraction Spherical Equivalent Diehl-Miller and Date-Miller Polynomial Equations

12 Target refractive error = (MRSE 020(MRSE change) (MRSE change) MRSE = Manifest Refraction Spherical Equivalent Diehl-Date-Miller Date Polynomial Equation

13 Myopic LASIK MRSE Change Target Induced by Refractive Error LASIK (D) to Achieve Emmetropia (D) Hyperopic LASIK MRSE Change Target Induced by Refractive Error LASIK (D) to Achieve Emmetropia (D) Look Up Tables

14 The Diehl-Miller equation was compared to other equations available through the ASCRS ( il l Based on patient information and measurement equipment available to us, the following methods could be evaluated: Masket, Modified-Masket, Shammas, Haigis-L, Clinical History Method, Feiz-Mannis, and Corneal Bypass Method. Comparison Study

15 This study constitutes the first-ever validation of the Diehl- Miller study. By applying the Diehl-Miller equation prospectively, we were able to show that it is accurate not only on the patient population from which it was derived, but also on an independent set of eyes. Thus, Diehl-Miller can be utilized in IOL power calculations to achieve postoperative emmetropia in post- LASIK eyes. The refractive effects of LASIK and PRK are similar, so the nomogram can probably be used on post-prk eyes. Discussion

16 By combining the 32 eyes from the Diehl-Miller study with the 23 eyes from the current Date-Miller study (for a ttl total of f55 eyes) we present a refined equation, which hih relates the MRSE change induced by LASIK to a target SE refractive error to be used in IOL power calculations. Associated look up tables are also presented, which eliminates the need for calculations. Thank You