Safety of femtosecond laser-assisted cataract surgery versus conventional phacoemulsification for cataract: A meta-analysis and systematic review.

Authors: Xu J, Chen X, Wang H, Yao K.

Geographical coverage: China, UK, Germany, France, Poland, Portugal, Spain, Australia, USA, and India.

Sector: Cataract surgery

Sub-sector: Treatment comparison

Equity focus: Not reported

Study population: Patients with cataract

Review type: Effectiveness review

Quantitative synthesis method: Meta-analysis

Qualitative synthesis method: Not applicable

Background: Globally, cataract is a major cause of visual impairment and blindness, especially in people over 50 years of age. With rising life expectancy and demand for better visual outcomes, cataract surgery has evolved from a vision-saving to a refractive procedure. Conventional phacoemulsification is widely used for its safety and efficiency, but femtosecond laser-assisted cataract surgery (FLACS), introduced in 2010, aims to enhance precision and outcomes. FLACS offers potential benefits such as improved capsulorhexis and reduced corneal damage. However, its safety remains debated, with studies reporting both increased and unchanged complication rates.

Objective: To compare the complications of femtosecond laser-assisted cataract surgery (FLACS) with those of conventional phacoemulsification surgery (CPS) for age-related cataracts.

Main findings: The review included 37 studies (Total: 24,806 eyes, FLACS group: 11,375, CPS group: 13,431). Of these, 19 were randomised controlled trials (RCTs) and 18 were prospective studies. The included studies represented a broad international distribution, primarily from Asia (especially China), Europe (UK, Germany, France, Poland, Portugal, Spain), and Oceania (Australia), with additional representation from North America (USA) and India. Meta-analysis showed no significant differences between the two groups in anterior capsule tear (odds ratio, OR = 1.75, 95% confidence interval [CI] = 0.82–3.73, P = 0.15) and posterior capsule tear (OR = 0.88, 95% CI = 0.59–1.31, P = 0.53). However, subgroup analysis revealed a significantly lower posterior capsule tear rate in the FLACS group within RCTs (OR = 0.49, 95% CI = 0.26–0.95, P = 0.04). Several FLACS-specific complications showed higher incidence rates compared to CPS. These included small pupil (OR = 3.05, P < 0.0001), corneal epithelial defect (OR = 4.94, P = 0.001), corneal haze (OR = 13.51, P = 0.002) and subconjunctival haemorrhage (OR = 6.42, P = 0.01).

On the other hand, FLACS demonstrated a lower incidence of certain intraoperative complications. These included Descemet’s membrane tear or trauma in studies using laser-assisted incisions (OR = 0.16, P = 0.02) and intraoperative floppy iris syndrome (IFIS) or iris trauma (OR = 0.35, P = 0.04). For other complications such as macular oedema, vitreous loss, posterior vitreous detachment, uveitis, posterior capsular opacification (PCO) and uncontrolled intraocular pressure, no statistically significant differences were found between the two groups.

Methodology: Searches were conducted in PubMed, Embase and the Cochrane Controlled Trials Register to identify RCTs or prospective cohort studies comparing FLACS and CPS. Studies involving participants with cataracts (without other eye disorders) and published in English or Chinese up to December 2021 were included in this review. Reference lists of relevant reviews were also carefully scanned to identify additional studies.

Two reviewers independently screened the identified studies. Any disagreements were resolved through discussion or, if needed, by consultation with a third reviewer. Three reviewers independently extracted relevant data, resolving any differences through discussion. The methodological quality of the included studies was assessed using the Cochrane Collaboration’s risk of bias tool for RCTs and the modified Newcastle–Ottawa Scale for cohort studies. Depending on the degree of heterogeneity, a fixed-effect or random-effects model meta-analysis was employed to synthesise the findings. Heterogeneity was assessed using the chi-square test and I² statistic. Sensitivity analysis was conducted to study the influence of a single study on the pooled estimates.

Applicability/external validity: The review noted that variations in surgical techniques, patient characteristics, follow-up durations, surgeon experience and femtosecond laser platforms across studies could influence outcomes. Additionally, the inability to blind participants and personnel in some trials may have introduced performance bias. The review highlighted the need for more standardised, long-term research.

Geographic focus: No geographical limits were applied in this review. The included studies were conducted in Asia (especially China), Europe (UK, Germany, France, Poland, Portugal, Spain) and Oceania (Australia), with additional representation from North America (USA) and India.

Summary of quality assessment: Overall, there is medium confidence in the review’s conclusions. The review employed a comprehensive search strategy with clearly defined inclusion and exclusion criteria. Study characteristics were well presented, and screening and data extraction were independently conducted by two reviewers. The findings were synthesised using meta-analysis. Heterogeneity was assessed, and sensitivity analyses were performed. Study quality was assessed using valid and reliable tools. However, the search was restricted to English- or Chinese-language publications. Additionally, no list of excluded studies was provided.