Evidence-based Synthesis Program 

(ESP)

Benefits and Harms of Femtosecond 

Laser Assisted Cataract Surgery 

A Systematic Review of the Evidence

VA Evidence-based Synthesis Program

Portland VA Medical Center

April 29, 2014
Evidence-based Synthesis Program 

(ESP)

Acknowledgments

Report Authors

o Ana Quiñones, PhD

o Ken Gleitsmann, MD, MPH 

o Michele Freeman, MPH 

o Rochelle Fu, PhD

o Maya O’Neil, PhD

o Makalapua Motu’apuaka, BS

o Devan Kansagara, MD

Presenters & Discussants

o Ken Gleitsmann, MD, MPH 

o James C. Orcutt, MD, PhD

o Elizabeth F. Baze, MD

Report Nominators, Technical 

Advisors, & Reviewers

o William Gunnar, MD, JD

o James Orcutt, MD, PhD

o Amy Chomsky, MD

o Glen Cockerham, MD

o Mary Daly, MD

o Mary Lawrence, MD, MPH

2 
Evidence-based Synthesis Program 

(ESP)

Disclosure

This research was funded by VA Quality Enhancement Research Initiative’s 

(QUERI) Evidence-based Synthesis Program, Project #05-225. The report 

was compiled by the Evidence-based Synthesis Program (ESP) Center 

located at the Portland VA Medical Center, Portland OR. The findings and 

conclusions are those of the author(s), and do not necessarily represent 

the views of the Department of Veterans Affairs or the United States 

government. Therefore, no statement in this article should be construed 

as an official position of the Department of Veterans Affairs. 

No investigators have any affiliations or financial involvement (e.g., 

employment, consultancies, honoraria, stock ownership or options, expert 

testimony, grants or patents received or pending, or royalties) that conflict 

with material presented in the report.
Evidence-based Synthesis Program 

(ESP)

VA Evidence-based Synthesis (ESP)

Program Overview

• Sponsored by VA Quality Enhancement Research Initiative (QUERI) 

Program.

• Established to provide timely and accurate syntheses/reviews of 

healthcare topics identified by VA clinicians, managers and policymakers, as they work to improve the health and healthcare of 

Veterans. 

• Builds on staff and expertise already in place at the Evidence-based 

Practice Centers (EPC) designated by AHRQ. Four of these EPCs are 

also ESP Centers: 

o Durham VA Medical Center; VA Greater Los Angeles Health Care 

System; Portland VA Medical Center; and Minneapolis VA Medical 

Center. 4 
Evidence-based Synthesis Program 

(ESP)

• Provides evidence syntheses on important clinical practice 

topics relevant to Veterans, and these reports help:

o develop clinical policies informed by evidence, 

o the implementation of effective services to improve patient 

outcomes and to support VA clinical practice guidelines and 

performance measures, and 

o guide the direction for future research to address gaps in 

clinical knowledge.

• Broad topic nomination process – e.g. VACO, VISNs, field – 

facilitated by ESP Coordinating Center (Portland) through 

online process: 

 http://www.hsrd.research.va.gov/publications/esp/TopicNomination.cfm
Evidence-based Synthesis Program 

(ESP)

• Steering Committee representing research and operations 

(PCS, OQP, ONS, and VISN) provides oversight and guides 

program direction.

• Technical Expert Panel (TEP)

o Recruited for each topic to provide content expertise.

o Guides topic development; refines the key questions.

o Reviews data/draft report.

• External Peer Reviewers & Policy Partners

o Reviews and comments on draft report

• Final reports posted on VA HSR&D website and disseminated 

widely through the VA. 

http://www.hsrd.research.va.gov/publications/esp/reports.cfm
Evidence-based Synthesis Program 

(ESP)

Current Report

Benefits and Harms of Femtosecond Laser 

Assisted Cataract Surgery (FLACS): 

A Systematic Review

(December 2013)

Full-length report available on the ESP website:

http://www.hsrd.research.va.gov/publications/esp/femtosecond.cfm

7 
Evidence-based Synthesis Program 

(ESP)

Overview of Today’s Presentation

• Background 

• Scope of the review

• Results 

• Limitations 

• Future research

• Implications - panel discussion

8 
Evidence-based Synthesis Program 

(ESP)

Background

• Current preferred method of removing cataracts includes creating 

manual corneal incisions and anterior capsulotomies, followed by 

phacoemulsification. 

• Recently these three manual procedures have been performed in an 

automated fashion with the use of the femtosecond laser (FSL). 

• Studies have suggested decreased phacoemulsification energy use 

with FSL cataract surgery and have examined the potential 

advantages of more precise corneal incisions and capsulotomy

formation.
Evidence-based Synthesis Program 

(ESP)

Background

• Cataract surgery is frequently performed in the VHA: more than 

49,000 performed in 2012.

• The VHA National Surgery Office has been tasked with making a 

recommendation on whether femtosecond lasers provide appropriate 

cost-benefit and risk-benefit ratios to support implementation for 

cataract surgery in the VA.

• The purpose of this systematic review is to examine the effectiveness 

and safety of femtosecond laser assisted cataract surgery (FLACS) 

relative to conventional cataract surgery. 
Evidence-based Synthesis Program 

(ESP)

Scope of the Review: Key Questions

• Key Question 1: What is the evidence that FLACS is associated 

with better outcomes than conventional cataract surgery? 

• Key Question 2:

a) What are the adverse effects that have been reported for FLACS? 

b) What is the risk of adverse effects from FLACS compared to the 

risk associated with conventional cataract surgery? 

• Key Question 3: What is the evidence that the experience of the 

surgeon is associated with adverse effects of FLACS? 

11
Evidence-based Synthesis Program 

(ESP)

Scope of the Review: Inclusion Criteria

Patients: Adults undergoing cataract surgery. 

Intervention: FSL technology used to assist or replace aspects of conventional 

cataract surgery, including corneal incisions, capsulotomy, and lens 

fragmentation. 

Comparator: Conventional cataract surgery, defined as small-incision, 

phacoemulsification with posterior-chamber intraocular lenses (IOL) implantation. 

Outcomes: 

• Visual acuity, short-term (post-op day 1) and long-term (after postop day 1, 

no upper limit) 

• Quality of life 

• Harms

Study design: 

• Controlled trials – randomized or non-randomized 

• Observational studies comparing FLACS to conventional cataract surgery 12
Evidence-based Synthesis Program 

(ESP)

13

Scope of the Review: Analytic Framework
Evidence-based Synthesis Program 

(ESP)

Scope of the Review: Exclusions

• Non-English language

• Non-adult study population

• No primary data (e.g., editorials) or non-systematic review article

• Outcomes not in scope (e.g., ex-vivo studies)

14
Evidence-based Synthesis Program 

(ESP)

Methods

• Search of databases (May 2013, updated October 2013)

• MEDLINE

• Cochrane library Database of Systematic Reviews and Central Register of 

Controlled Trials

• Clinicaltrials.gov

• FDA premarket notification 510(k) summaries

• Conference proceedings of ophthalmologic societies and topic specific journals

• Additional articles and reviews obtained from reference lists and reviewers 

• Data abstraction 

• Assessment of study quality

• Review of evidence: qualitative synthesis and meta-analysis 

15
Evidence-based Synthesis Program 

(ESP)

Results: Search Yield

16

468 from electronic databases: 

 76 Medline 

 3 Cochrane library (Trials and DARE) 

 14 Clinicaltrials.gov 

6 FDA premarket 510(k) summaries

 369 Ophthalmology or cataract surgery journals

436 from manual searches: 

Conference proceedings

Reference lists 

Unpublished/ongoing 

studies

904 total titles and abstracts

70 articles and abstracts selected for full-text review

834 excluded 
Evidence-based Synthesis Program 

(ESP)

Results: Search Yield, continued

17

15 included studies: 

- 9 on benefits (KQ1)

- 9 on harms (KQ2)

- 2 on risks in relation to 

surgeon experience (KQ3) 

36 excluded articles 

70 articles and abstracts selected for full-text review

19 abstracts of 

unpublished/

ongoing studies
Evidence-based Synthesis Program 

(ESP)

Poll Question

(Pick one answer)

What best describes your professional training?

1. Ophthalmologist

2. Optometrist

3. Researcher

4. Other 

18
Evidence-based Synthesis Program 

(ESP)

Poll Question (Practicing ophthalmologists 

pick one answer)

What best describes your experience with 

FLACS?

1. Practicing ophthalmologist with FLACS 

experience

2. Practicing ophthalmologist planning to 

perform FLACS in the future

3. Practicing ophthalmologist not planning to 

perform FLACS in the future

19
Evidence-based Synthesis Program 

(ESP)

Results: Key Question 1

What is the evidence that FLACS is associated with 

better outcomes than conventional cataract surgery?

o Visual outcomes (CDVA) were similar between groups

o EPT outcomes were mixed; results were either comparable between 

groups, or favoring FSL groups

o Meta-analysis of CDVA and EPT outcomes noted heterogeneity precluding 

calculation of reliable summary effect estimate

o No studies addressed quality of life measures 
Evidence-based Synthesis Program 

(ESP)

Results: Forest Plot of CDVA Studies 

 

21

Figure 1. 

Corrected distance 

visual acuity in studies 

comparing FLACS with 

conventional cataract 

surgery
Evidence-based Synthesis Program 

(ESP)

Results: Forest Plot of EPT Studies 

 

22

Figure 2. 

Effective 

phacoemulsification 

time in studies 

comparing FLACS 

with conventional 

cataract surgery
Evidence-based Synthesis Program 

(ESP)

Results: Key Question 2a

What are the adverse effects that have been reported 

for FLACS? 

o Laser interface events

o Several studies noted significant numbers of patients required a second docking attempt 

without adverse effects

o Patients with corneal scarring or distortion, kyphosis, claustrophobia, and excessive 

movements were excluded from Laser treatment groups 

o Intraocular pressure events (IOP)

o All FSL docking platforms have been shown to cause increases in IOP; a concern for 

patients with coexistent glaucoma

o Two studies of IOP effects were included in this review which used only the Catalys FSL 

platform

o One case series (N=100) noted mean IOP increased to 27.6+-5.5mm Hg

o Another case series (N=25) noted mean IOP increased to 36.0+-4.4 mm Hg
Evidence-based Synthesis Program 

(ESP)

Results: Key Question 2b

What is the risk of adverse effects from FLACS 

compared to the risk associated with conventional 

 cataract surgery? 

o Comparative risks noted similar findings for post-operative corneal edema, 

macular thickness and morphology

o Methodological concerns were noted for these comparative results as 

enrollment criteria varied between conventional and FSL surgery groups

 
Evidence-based Synthesis Program 

(ESP)

Results: Key Question 3 

What is the evidence that the experience of the surgeon 

is associated with adverse effects of FLACS? 

o

o

Overall findings were mixed in studies comparing initial to subsequent 

groups of patients undergoing FLACS 

One study noted surgeons who had “extensive” refractive surgery 

experience had fewer complications in their initial FLACS patient groups 

than did surgeons without previous refractive surgery experience

o Methodological concerns were noted in enrollment criteria used for the 

FSL versus conventional surgery groups
Evidence-based Synthesis Program 

(ESP)

Limitations of the evidence

• Methodological concerns

o Small sample sizes

o Selected samples excluded patients unsuitable for FLACS, e.g.,

 Patients with dense cataracts

 Orbital anatomy incompatible with successful laser docking

• Conflicts of interest

o Same team replication

o Most studies funded by industry
Evidence-based Synthesis Program 

(ESP)

Summary of the evidence: benefits

 

27

Outcome

N studies

(combined 

sample size)

Findings

Strength 

of 

Evidence

Comments

Visual 

acuity

2 RCTs (N=189)

4 NRCS (N=306)

No 

significant 

differences

Low 

No differences found in the randomized trials. 

Unclear risk of bias for trials. 

Low consistency, coherence, and applicability of 

estimated effects across studies, small to medium 

sample sizes, and conflicts of interest.

Effective

phacoemulsif. 

time

1 RCT (N=76)

4 NRCS (N=615)

1 NCS (N=160)

Mixed 

findings Low

Trial found no significant reduction in EPT with FSL.

Two large nonrandomized studies (N=550) reported 

significant reductions with FLACS. 

No significant differences in other studies. 

Unclear risk of bias for trial. 

Low consistency, coherence, and applicability of 

estimated effects across studies. 

Conflicts of interest.

Quality of 

life None None No 

evidence

None of the included studies reported on quality of 

life outcomes. 
Evidence-based Synthesis Program 

(ESP)

Summary of the evidence: harms

 

28

Outcome

N studies

(combined 

sample size)

Findings Strength of 

Evidence Comments

Intraoperative 

complications

3 NRCS 

(N=1,900)

3 NCS 

(N=285)

Higher IOP for 

FLACS; 

Few additional 

complications for 

FLACS 

Moderate to 

Low

Low incidence of complications with FLACS, 

though increases in IOP reported across 

studies. 

Low applicability of estimated effects. 

Postoperative 

complications

1 RCT 

(N=76)

1 NRCS 

(N=150)

1 NCS 

(N=160)

Mixed findings Low

Trial found no significant differences. 

Cohort study (N=150) found significantly 

reduced endothelial loss with FLACS. 

Unclear risk of bias for trial.

Low consistency and coherence of estimated 

effects across studies, small to medium sample 

sizes. 

Conflicts of interest.

Costs None None No evidence No studies reported data on costs of FLACS 

compared to conventional cataract surgery.
Evidence-based Synthesis Program 

(ESP)

Future Research Suggestions

• RCTs with larger sample sizes to detect rare events

• Applicability of FSL technology to patients with dense 

cataracts, glaucoma, and corneal pathology

• Head to head trials between FSL platforms

• Cost-benefit ratio
Evidence-based Synthesis Program 

(ESP)

Questions?

If you have further questions, 

feel free to contact:

Ken Gleitsmann, MD, MPH

ken.gleitsmann@gmail.com

The full report and cyber seminar presentation is available on the ESP website: 

http://www.hsrd.research.va.gov/publications/esp/
Evidence-based Synthesis Program 

(ESP)

Panel Discussion