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Improving intraocular lens power calculation with femtosecond laser biometry data

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Session Details

Session Title: Cataract Surgery Outcomes: IOL Power Calculations

Session Date/Time: Sunday 08/10/2017 | 14:30-16:00

Paper Time: 15:18

Venue: Meeting Center Room I

First Author: : M.Pyfer USA

Co Author(s): :    T. Arlow   E. Hufnagel                 

Abstract Details


Femtosecond laser assisted cataract surgery (FLACS) captures detailed anatomical information using intraoperative high resolution swept source anterior segment ocular coherence tomography (OCT). The OCT data is used to create a three dimensional model to guide femtosecond laser corneal incisions, capsulotomy and lens fragmentation. However, this information is not currently being utilized in power selection for intraocular lens (IOL) implants. The goal of this study is to determine if the biometry derived from the Catalys® FLACS anterior segment OCT can more accurately predict postoperative refractive outcome compared to standard preoperative measurements from the IOL Master®.


Private practice and surgery center affiliated with Wills Eye Hospital in Philadelphia, Pennsylvania, USA.


A retrospective chart review was conducted of 52 contiguous cases, performed by one surgeon between May 2015 and January 2016, that had preoperative IOL Master® measurements before FLACS using the Catalys® laser. The Catalys® OCT biometry was extracted, including anterior chamber depth (ACD), lens thickness (LT), lens meridian position (LMP) and corneal horizontal white-to-white (WTW). This data was then used to calculate the predicted postoperative refraction using the Barrett II and Holladay II formulas with the actual IOL implant power. Also, LMP was compared to the calculated effective lens position (ELP) from the Haigis and SRK-T formulas.


Catalys® measures a statistically significant (P<0.01) deeper ACD and shorter WTW than IOL Master®. Use of W2W, ACD and LT from the Catalys® anterior segment OCT, instead of IOL Master®, more accurately predicted the postoperative refractive outcome (P<0.05) when using Barrett II and Holladay II formulas. The two formulas were not significantly different from each other. The LMP measured by Catalys® closely approximates the calculated ELP from the Haigis and SRK-T formulas.


The anterior segment anatomical measurements used for IOL power calculations were significantly different when measured by the Catalys® FLACS OCT compared to the IOL Master®. Using the FLACS OCT data resulted in more accurate prediction of postoperative refractive outcome. Also, FLACS OCT data may be used to estimate the postoperative effective lens position, which could further improve the IOL power calculation.

Financial Disclosure:


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