Defining the ideal femtosecond laser capsulotomy

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Abstract

Purpose

We define the ideal anterior capsulotomy through consideration of capsular histology and biomechanics. Desirable qualities include preventing posterior capsular opacification (PCO), maintaining effective lens position (ELP) and optimising capsular strength.

Methods

Laboratory study of capsular biomechanics and literature review of histology and published clinical results.

Results

Parameters of ideal capsulotomy construction include complete overlap of the intraocular lens to prevent PCO, centration on the clinical approximation of the optical axis of the lens to ensure concentricity with the capsule equator, and maximal capsular thickness at the capsulotomy edge to maintain integrity.

Conclusions

Constructing the capsulotomy centred on the clinical approximation of the optical axis of the lens with diameter 5.25 mm optimises prevention of PCO, consistency of ELP and capsular strength.

Related collections

Most cited references 23

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Sources of error in intraocular lens power calculation.

N E Sverker Norrby (2008)

To identify and quantify sources of error in the refractive outcome of cataract surgery. AMO Groningen BV, Groningen, The Netherlands. Means and standard deviations (SDs) of parameters that influence refractive outcomes were taken or derived from the published literature to the extent available. To evaluate their influence on refraction, thick-lens ray tracing that allowed for asphericity was used. The numerical partial derivative of each parameter with respect to spectacle refraction was calculated. The product of the partial derivative and the SD for a parameter equates to its SD, expressed as spectacle diopters, which squared is the variance. The error contribution of a parameter is its variance relative to the sum of the variances of all parameters. Preoperative estimation of postoperative intraocular lens (IOL) position, postoperative refraction determination, and preoperative axial length (AL) measurement were the largest contributors of error (35%, 27%, and 17%, respectively), with a mean absolute error (MAE) of 0.6 diopter (D) for an eye of average dimensions. Pupil size variation in the population accounted for 8% of the error, and variability in IOL power, 1%. Improvement in refractive outcome requires better methods for predicting the postoperative IOL position. Measuring AL by partial coherence interferometry may be of benefit. Autorefraction increases precision in outcome measurement. Reducing these 3 major error sources with means available today reduces the MAE to 0.4 D. Using IOLs that compensate for the spherical aberration of the cornea would eliminate the influence of pupil size. Further improvement would require measuring the asphericity of the anterior surface and radius of the posterior surface of the cornea.

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Femtosecond laser capsulotomy.

J Talamo, N. Friedman, M S Blumenkranz … (2011)

To evaluate a femtosecond laser system to create the capsulotomy. Porcine and cadaver eye studies were performed at OptiMedica Corp., Santa Clara, California, USA; the human trial was performed at the Centro Laser, Santo Domingo, Dominican Republic. Experimental and clinical study. Capsulotomies performed by an optical coherence tomography-guided femtosecond laser were evaluated in porcine and human cadaver eyes. Subsequently, the procedure was performed in 39 patients as part of a prospective randomized study of femtosecond laser-assisted cataract surgery. The accuracy of the capsulotomy size, shape, and centration were quantified and capsulotomy strength was assessed in the porcine eyes. Laser-created capsulotomies were significantly more precise in size and shape than manually created capsulorhexes. In the patient eyes, the deviation from the intended diameter of the resected capsule disk was 29 μm ± 26 (SD) for the laser technique and 337 ± 258 μm for the manual technique. The mean deviation from circularity was 6% and 20%, respectively. The center of the laser capsulotomies was within 77 ± 47 μm of the intended position. All capsulotomies were complete, with no radial nicks or tears. The strength of laser capsulotomies (porcine subgroup) decreased with increasing pulse energy: 152 ± 21 mN for 3 μJ, 121 ± 16 mN for 6 μJ, and 113 ± 23 mN for 10 μJ. The strength of the manual capsulorhexes was 65 ± 21 mN. The femtosecond laser produced capsulotomies that were more precise, accurate, reproducible, and stronger than those created with the conventional manual technique. Copyright © 2011 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

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Surgical outcomes and safety of femtosecond laser cataract surgery: a prospective study of 1500 consecutive cases.

Timothy V Roberts, Michael Lawless, Shveta J. Bali … (2013)

To report the surgical outcomes and safety of femtosecond (FS) laser cataract surgery (LCS) with greater surgeon experience, modified techniques, and improved technology.

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Author and article information

Journal

Journal ID (nlm-ta): Br J Ophthalmol

Journal ID (iso-abbrev): Br J Ophthalmol

Journal ID (hwp): bjophthalmol

Journal ID (publisher-id): bjo

Title: The British Journal of Ophthalmology

Publisher: BMJ Publishing Group (BMA House, Tavistock Square, London, WC1H 9JR )

ISSN (Print): 0007-1161

ISSN (Electronic): 1468-2079

Publication date (Print): August 2015

Publication date (Electronic): 31 March 2015

Volume: 99

Issue: 8

Pages: 1137-1142

Affiliations

[1 ]Oregon Health & Science University , Eugene, Oregon, USA

[2 ]Lensar, Orlando, Florida, USA

[3 ]College of Optometry, University of Houston , Houston, USA

Author notes

[Correspondence to ] Mark Packer MD, 1400 Bluebell Ave, Boulder, CO 80302, USA; mark@ 123456markpackerconsulting.com

Presented in part at the Royal Hawaiian Eye Meeting, Poipu, Kauai, USA, 20 January 2014.

Article

Publisher ID: bjophthalmol-2014-306065

DOI: 10.1136/bjophthalmol-2014-306065

PMC ID: 4518749

PubMed ID: 25829488

SO-VID: 52c343c9-0435-41f5-b6f7-68e692b3ee82

License:

This is an Open Access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/