Femtosecond laser-assisted cataract surgery versus conventional phacoemulsification cataract surgery: a meta-analysis of randomized controlled trials

Abstract

The study aims to compare the efficacy/safety of femtosecond laser-assisted cataract surgery (FLACS) vs. conventional phacoemulsification cataract surgery (CPCS). A systematic search/analysis of PubMed, Embase, Cochrane CENTRAL, and ClinicalTrials.gov up to January 2023 was conducted without date/language restrictions. Weighted mean differences, risk ratios, and Hedges’ g with 95% confidence intervals were calculated. The stability of results was assessed using trial sequential analysis (TSA). International Prospective Register of Systematic Reviews Registration No. PROSPERO CRD42023393323. Forty-six randomized controlled trials (8,871 eyes) revealed that FLACS yielded a significantly better corrected distance visual acuity (CDVA) 1 week postoperatively (P = 0.011) with no significant differences in CDVA beyond 1 week (P = 0.161, 0.429, 0.403), or in uncorrected distance visual acuity (P = 0.171, 0.136, 0.322, 0.149), spherical equivalent, or surgically induced astigmatism. Concerning safety outcomes, no significant differences were observed in overall complications (P = 0.999). These findings were supported by TSA. Ultimately, the overall complications, patient-reported health, visual, and daily-activity outcomes were not significantly different between FLACS and CPCS. Regarding extended-term and patient-centered outcomes, we identified no substantial disparities in visual acuity, complications, or patient-reported outcomes between FLACS and CPCS. Subgroup analysis showed consistent efficacy and safety across diverse laser platforms. Notably, FLACS exhibited no clear cost-effectiveness advantage over CPCS.

Supplementary Information

The online version contains supplementary material available at 10.1038/s41598-025-13174-1.

Introduction

Cataracts are a significant global burden influencing blindness and affecting millions of individuals annually. The World Health Organization estimates that 65.2 million cases of cataract-related blindness can be prevented globally.¹ Presently, the surgical removal of cataracts is the only therapy.² Conventional phacoemulsification cataract surgery (CPCS) is widely employed for cataract removal; but its success relies heavily on surgical expertise.³ An alternative approach termed femtosecond laser-assisted cataract surgery (FLACS) that uses ultrashort pulses to reduce energy output has attracted increasing attention.⁴

Previous studies have highlighted the benefits of FLACS, including improved capsulotomy circularity, reduced phacoemulsification time, and corneal endothelial cell loss.^5–7 However, these advantages are not patient-centered and do not consider patient well-being or impact on quality of life. FLACS also poses unique complications such as suction issues and nonperforated laser corneal incisions, which may necessitate manual intervention.⁸ Thus, there is on-going debate regarding the optimal surgical technique.

While previous reviews and analyses have not definitively favored either technique in terms of efficacy, such as CDVA and UDVA, or safety outcomes, including overall complications.^9–12 In the study reported by Day et al.⁹ in 2016, the authors found minimal differences in postoperative visual acuity and uncertainty regarding complications such as capsular tears and macular edema. Similarly, another study performed in 2016 by Popovic et al.¹⁰ reported the absence of significant differences in visual outcomes and overall complications. However, posterior capsular tears were more common after this procedure compared with CPCS. A study reported in 2020 by Kolb et al.¹² found better visual acuity with FLACS after 1–3 months; in turn, it also identified more frequent anterior capsule ruptures and provided conflicting results regarding posterior capsular tears.¹³ Lastly, a study by Narayan et al.¹⁴ in 2023 reported probably little or no difference in terms of intraoperative and postoperative complications, postoperative visual acuity and quality of life. However, these studies did not perform a meta-analysis of patient-reported outcomes and overlooked some postoperative complications, such as posterior capsular opacification. Given recent substantial randomized controlled trials (RCTs),^8,15–18 an updated meta-analysis is warranted to clarify the benefits of FLACS compared with those of CPCS and guide clinical decision-making.

This meta-analysis, accompanied by a trial sequential analysis, comprehensively evaluates FLACS versus CPCS to assess efficacy, safety, and patient satisfaction, with CDVA and UDVA as the primary outcomes. Through meticulous literature review and data analysis, we aim to determine whether FLACS offers advantages over CPCS in these aspects, with a focus on RCTs to minimize bias. Our findings hold the potential to enhance clinical decision-making and elevate the quality of care for cataract surgery patients.

Methods

Study design

This meta-analysis aimed to compare the efficacy and safety of FLACS with CPCS. The study adhered to the recommendations outlined in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement (Table S1), and was registered on the PROSPERO website (Registration No. PROSPERO 2023 CRD42023393323).

Inclusion and exclusion criteria

Inclusion Criteria:

1. RCTs that included human participants who underwent cataract surgery.

2. Studies reported visual, surgical, complications or patient-reported outcomes for both the FLACS and CPCS study arms

3. Participants were adults aged 18 years or older

Exclusion Criteria:

1. Studies that had overlapping participants or failed to report relevant data for use in this analysis.

2. Studies that involved participants with ophthalmological conditions that could affect the outcome, such as amblyopia, glaucoma, diabetic retinopathy, macular degeneration, or Fuchs’ endothelial dystrophy.

3. Studies that involved a specific device, like toric intraocular lens implantation, used in only one arm.

4. Situations in which a particular medication, such as an NSAID, was used exclusively in one arm.

Outcome Measures

Visual Outcomes

• Corrected distance visual acuity (CDVA)

• Uncorrected distance visual acuity (UDVA)

• Spherical equivalent (SE)

• Surgically induced astigmatism (SIA)

Surgical Outcomes

• Effective phacoemulsification time (EPT)

• Cumulative dissipated energy (CDE)

• Endothelial cell loss (ECL)

• Central corneal thickness (CCT)

Complications

• Intraoperative complications

  • Anterior capsular rupture
  • Posterior capsular tear
• Postoperative complications

  • Macular edema
  • Corneal edema
  • Elevated IOP
  • Posterior capsular opacification (PCO)
• Other complications

  • Suction loss
  • Incomplete phacofragmentation pattern
  • Nonperforated laser corneal incisions
  • Decentered capsulotomy
  • Decentered intraocular lens (IOL)

Patient-reported Outcome Measures (PROMs)

• Patient-reported health outcomes

• Patient-reported visual outcomes

• Patient-reported daily-activity outcomes

Search methods for identifying studies

A comprehensive search was conducted in PubMed, Embase, Cochrane CENTRAL, and ClinicalTrials.gov by three independent authors (S.-H. Lee, Y.-C. Chiu, and P.-C. Tsai) using the following keywords: (femtosecond OR femto laser OR laser-assisted OR FLACS) AND (phaco OR phacoemulsification OR manual OR conventional OR standard phacoemulsification) AND cataract, from the earliest record to January 24, 2023. No language restrictions were imposed (Table S2).

The population, intervention, comparison, and outcome setting of the current meta-analysis was as follows: (1) P: cataract patients; (2) I: FLACS; (3) C: CPCS; and (4) O: outcomes related to efficacy, safety, and patient satisfaction within 1 year.

Study selection

Three authors (S.-H. Lee, Y.-C. Chiu, and P.-C. Tsai) conducted a preliminary review of the titles and abstracts. The full articles were then analyzed to select the studies that met the predefined criteria. Any disagreements between the reviewers were resolved through careful discussion until a consensus was reached. Detailed information on excluded studies and the reasons for their exclusion can be found in Table S3.

Risk of bias assessment

To investigate the methodological quality of the studies included in the present analysis, the Cochrane risk of bias tool for randomized trials version 2 (RoB 2) was used. The tool consisted of six main items: the randomization process, intervention adherence, missing outcome data, outcome measurement, selective reporting, and overall risk of bias. Three reviewers (S.-H. Lee, Y.-C. Chiu, and P.-C. Tsai) independently assessed the risk of bias of the included studies following the recommendations in the Cochrane Handbook of Systematic reviews 5.1. Disagreements were resolved through consensus or by another authors (J.-H. Wang and C.-J. Chiu).

Data extraction

Data were extracted by three authors (S.-H. Lee, Y.-C. Chiu, and P.-C. Tsai) from the included studies and included demographic data, study design, details of both surgeries, and values of visual, surgical, safety, and other relevant outcomes. In situations in which the data were unavailable in the published articles, the corresponding authors were contacted to obtain the original data.

Duration of the follow-up

The postoperative outcomes were monitored through four follow-up period categories based on time after surgery. Data at 1 week or within 1 week post-surgery were categorized as very short term. Short-term data were collected between 1 week and 1 month, or exactly at 1 month. Middle-term data were between 1 and 3 months, or exactly at 3 months. Extended-term data were collected after 3 months after surgery. This classification system enabled precise time-based outcome analysis, visually presented in a forest plot created using Comprehensive Meta-Analysis (CMA).

Data synthesis and analysis

Due to the diverse populations in enrolled studies, we employed a random effects model using CMA version 4.0 software. A two-tailed P value < 0.05 was considered significant. Effect sizes were measured using three strategies: weighted mean differences (WMDs) with 95% CIs for continuous outcomes, risk ratios with 95% CIs for binary outcomes, and Hedges’ g with 95% CIs for outcomes involving different measurement tools. Hedges’ g of 0.2, 0.5, and 0.8 represented small, moderate, and large effects. In addition, I² and Cochran’s Q statistics were used to assessed heterogeneity (25%, 50%, and 75% for low, moderate, and high heterogeneity).

We conducted a subgroup analysis when the I² was above 50%, based on different laser platforms. Additionally, publication bias was explored with Egger’s test when more than 10 trials contributed data. Conversely, sensitivity analysis confirmed meta-analysis robustness through one study removal.

Trial sequential analysis

We utilized TSA 0.9.5.10 beta software to minimize errors and confirm the conclusiveness of the meta-analysis. Employing a random effects model, we created a cumulative Z curve to visualize the evolving evidence. We maintained a 5% alpha level and 80% statistical power to achieve robustness. Furthermore, we utilize the diversity (D²) metric, as suggested by the included trials,¹⁹ to enhance the precision of our analysis.

For visual acuity, a fixed mean difference of 0.1^20,21 was guided by minimal important difference improvement. Aligned with TSA guidelines, dichotomous outcomes used statistical information (Fisher information) to determine information size of overall complications.²² A predefined 10% relative risk reduction benchmark was applied.

A cumulative Z curve that intersects the monitoring boundaries or enters the futility region provides sufficient evidence for acceptance or rejection, eliminating the need for further studies. If the Z curve does not cross these boundaries or lacks the required information size, further research is considered necessary to make definitive conclusions.²³.

Results

Literature search

Our search and selection processes are outlined in Fig. 1. We initially retrieved a total of 1,491 studies from the database search by adhering to the PRISMA guidelines.²⁴ After eliminating duplicate records, we carefully reviewed the titles and abstracts of the remaining studies, ultimately identifying 85 studies for full-text screening. Finally, 46 studies were included in our meta-analysis.

Fig. 1.

PRISMA Flowchart of literature search and study selection.

Characteristics of the included studies

Table S4 presents the general attributes of the studies included in our meta-analysis. Encompassing a total of 8,871 eyes, with 4,479 eyes in the FLACS group and 4,392 in the CPCS group, these studies were RCTs conducted from 2011 to 2022. Language diversity was accommodated, with three studies in Chinese and one in Spanish. Geographically, Europe held the majority (29/50 = 58%), followed by 12 studies in Asia and eight in America. The mean age of the participants ranged from 52.8 to 79.1 years. Sample sizes varied from 40 to 1,389 eyes, and the follow-up time spanned from the day of the operation (0 days) to 1 year postoperatively. These studies used five distinct laser platforms, including Catalys™ (Johnson & Johnson Surgical Vision), Femto LDV Z8 (Ziemer Ophthalmic Systems AG), LENSAR® (LENSAR Inc.), LenSx® (Alcon Laboratories Inc.), and VICTUS® (Bausch + Lomb Incorporated).

Risk of bias assessment

The results of the ROB2.0 risk of bias assessment were presented in Table S5 and Fig. S1. Because of the failure to use a double-blind design, the performance bias was consistently high. Otherwise, most studies exhibited a low risk of bias in the remaining domains.

Visual outcomes

For our meta-analysis, we transformed sample-based estimates of the group-level mean and SD values of visual acuity across different scales of measurement for studies with a reasonable size (N ≥ 30).²⁵.

The analysis revealed that FLACS group exhibited a significantly higher level of very short–term (≤ 1 week) CDVA compared with CPCS group (WMD: − 0.03, 95% CI − 0.05 to − 0.01; P = 0.011). However, no statistically significant differences were observed in CDVA during later follow-up periods (Fig. 2). In addition, UDVA did not exhibit statistically significant differences at any of the time points examined (Fig. 3).

Fig. 2.

Meta-analysis of corrected distance visual acuity (CDVA) of femtosecond laser-assisted cataract surgery (FLACS) compared with conventional phacoemulsification cataract surgery (CPCS).

Fig. 3.

Meta-analysis of uncorrected distance visual acuity (UDVA) of femtosecond laser-assisted cataract surgery (FLACS) compared with conventional phacoemulsification cataract surgery (CPCS).

The findings of TSA are depicted in Figs. 4 and 5, and Fig. S2–7. Notably, the cumulative Z curve of extended-term (> 3 months) CDVA and UDVA intersected the futility boundaries, reinforcing the reliability of the results that the surgical technique does not yield superior visual acuity outcomes.

Fig. 4.

Trial sequential analysis of extended-term corrected distance visual acuity (CDVA) of femtosecond laser-assisted cataract surgery (FLACS) compared with conventional phacoemulsification cataract surgery (CPCS).

Fig. 5.

Trial sequential analysis of extended-term uncorrected distance visual acuity (UDVA) of femtosecond laser-assisted cataract surgery (FLACS) compared with conventional phacoemulsification cataract surgery (CPCS).

There were no significant differences in SE between the two groups at any time point (Fig. S8). Moreover, the comparison of SIA between the two groups revealed no significant differences (Fig. S9).

Surgical outcomes

Surgical outcomes analysis revealed significant differences between FLACS and CPCS. EPT was notably shorter for FLACS (WMD: − 1.74, 95% CI − 2.14 to − 1.34; P < 0.001; Fig. S10, as was CDE (WMD: − 2.47, 95% CI − 3.02 to − 1.91; P < 0.001; Fig. S11). Postoperative ECL showed reduction with FLACS in the very short term (WMD: − 3.60, 95% CI − 7.07 to − 0.14; P = 0.042) but not significantly different in short, middle (> 1 month, ≤ 3 months), and extended terms (Fig. S12 In the short term, CCT was significantly thinner in the FLACS group (WMD: − 4.46, 95% CI − 8.80 to − 0.12; P = 0.044), whereas differences were not significant in very-short, middle, or extended terms (Fig. S13).

Complications

No significant differences were observed in overall complications in our study (Fig. S14). This observation was further affirmed by the TSA results (Fig. 6), where the cumulative Z curve intersected the futility boundaries. This intersection underscores that the surgical techniques have a comparable complication rate.

Fig. 6.

Trial sequential analysis of complications of femtosecond laser-assisted cataract surgery (FLACS) compared with conventional phacoemulsification cataract surgery (CPCS).

Intraoperative complications

The FLACS group exhibited a 1.24% incidence (11 cases) of anterior capsular rupture, whereas the CPCS group had a 1.00% incidence (9 cases). The incidence of posterior capsular tears was 0.89% (13 cases) in the FLACS and 1.59% (23 cases) in the CPCS group. No significant difference in incidence was observed between the two groups (Figs S15 and S16).

Postoperative complications

Regarding the postoperative complications, no significant differences were observed in various aspects, such as macular edema within 3 months and 12 months, corneal edema within 3 months, elevated IOP within 24 h, and PCO within 12 months (Figs S17, S18, S19, and S20).

Patient-reported outcome measurements

We evaluated five studies that used PROMs as their primary endpoint.^{15,17,26–28} These studies used various questionnaires, such as EQ-5D-3L, EQ-5D VAS, and Cat-PROM5, as well as questions asking patients to rate their experience as excellent, good, or neutral. The data were categorized into three subgroups based on the questionnaire type or question: patient-reported health outcomes, visual outcomes, and daily-activity outcomes. The analysis of these three PROM subcategories revealed an absence of significant differences between the FLACS and CPCS groups (Fig. S21).

Laser platform subgroup analysis

Among the five commercially available femtosecond laser cataract surgery systems—Catalys, Femto LDV Z8, LENSAR, LenSx, and VICTUS—outcomes specific to each manufacturer were considered. We found no significant differences between groups in CDVA, UDVA, and SE were observed (P = 0.456, 0.839, 0.313; Figs S22, S23, and S24). However, significant differences between groups were found in CDE, CCT, and ECL (P = 0.021, 0.038, 0.001; Figs S25, S26, and S27). Specifically, CDE was significantly lower in FLACS with Catalys (P < 0.001), LenSx (P < 0.001), and VICTUS (P = 0.008), while no significant differences were found for LDV Z8 and LENSAR (Fig. S24. FLACS with LenSx resulted in thinner CCT (P = 0.002), and Catalys and LDV Z8 led to lower ECL (P < 0.001 for both) (Figs S26 and S27).

Sensitivity analysis

The sensitivity analysis was carried out comprehensively. Consistent results were obtained, with the exception of the subgroups assessing “CCT in the very short term.” Furthermore, the exclusion of the studies reported by Conrad-Hengerer in 2014²⁹, Oka in 2021³⁰, or Schweitzer in 2020⁸ yielded a significantly thinner CCT in the very short term in FLACS group (WMD: − 62.76, 95% CI − 144.54 to − 10.99; P = 0.018; Fig. S28).

Publication bias

A low evidence of publication bias by Egger’s test was observed (Table S6).

Discussion

This updated meta-analysis aimed to thoroughly compare FLACS and CPCS regarding clinical outcomes and complications. Our findings showed early advantages of FLACS in CDVA, ECL, and CCT, as well as significant distinctions in EPT and CDE. However, considering extended-term perspectives, as corroborated by TSA, no discrepancies emerged in terms of UDVA, CDVA, or complications, which are outcomes that directly impact patient well-being. Furthermore, no significant differences were detected in terms of other complications and patient-reported outcomes. Laser platform subgroup analysis yielded diverse results, suggesting unique benefits for each platform.

Our investigation included 46 RCTs, significantly expanding the evidence base by more than doubling the number of studies found in prior meta-analyses.^12,31,32 This larger sample size, coupled with the application of TSA, allowed us to ascertain the robustness and conclusiveness of our findings. Unlike many previous meta-analyses, which often focused primarily on visual and surgical parameters, our study comprehensively incorporated additional patient-centered outcomes, such as postoperative PCO and PROMs. Furthermore, our meta-analysis included non-English studies, enabling a broader and more refined evaluation of intervention effectiveness and reflecting a patient-centric approach to healthcare. While we acknowledge the recent Cochrane review by Narayan et al. in 2023,³³ which similarly concluded little or no difference in most outcomes, our work provides more robust and conclusive evidence through its substantially larger dataset and the rigorous application of TSA.

Visual efficacy analysis

In the field of cataract surgery, patient satisfaction is heavily influenced by visual acuity and refractive outcomes. Consistent with previous meta-analyses, our investigation revealed that the sole statistically significant discrepancy in CDVA detected between the FLACS and CPCS group emerged at the 1-week postoperative time point, with no further differences identified. As shown by our TSA results, CDVA and UDVA exhibited no divergence over the extended-term, obviating the necessity for further investigation. In addition, no variations were observed in SE across all time points. These findings are consistent with the results of the postoperative visual questionnaire administered by Day et al.,¹⁵ who reported no notable differences between the two groups at either 3 or 12-month after surgery.

Furthermore, our findings support the results of previous meta-analyses¹² of SIA, which is another factor affecting visual acuity that results from wound healing at the corneal incision site, revealing no significant differences in SIA between the FLACS and CPCS groups. Owing to the lack of a classification system for severe or complex cataracts in the included studies, a comparison could not be performed.

Surgical analysis

Our meta-analysis highlights the superiority of FLACS over CPCS in terms of surgical outcomes, particularly EPT and CDE. Notably, EPT-related oxidative stress is closely tied to phacoemulsification.³⁴ Conversely, lower CDE indicates lower ultrasound energy, potentially leading to quicker recovery.³⁵ Interestingly, minor ECL and CCT differences in the short term between FLACS and CPCS faded over time, likely due to endothelial cell recovery through division.³⁶ For patients with endothelial dysfunction like Fuchs Endothelial Corneal Dystrophy (FED), FLACS might offer benefits, as proposed by Fan et al.³⁷. However, Krarup et al.³⁸ suggested significant ECD sampling measurement errors for FED patients, making these parameters unsuitable for this group.

Complications

Intraoperative complications

In our analysis involving 9,268 eyes, the intraoperative complication rate did not differ significantly between the groups, with early issues related to FLACS attributed to its learning curve. Anterior capsular rupture and posterior capsular tear are major complications of cataract surgery and associated with poor visual outcomes and even retinal detachment.³⁹ However, the varying theories regarding their occurrence in FLACS versus CPCS complicate the interpretation.^12,31.

In their analysis including RCTs and observational studies, Kolb et al.¹² detected a significant increase in anterior capsular rupture with FLACS over CPCS. They linked this result to manual intervention due to incomplete capsulotomies and extra laser pulses. However, in the RCT subgroup analysis, the rupture link was insignificant. Popovic et al.¹⁰ found a higher posterior capsular tears for FLACS, while Kolb et al.¹² did not. Conversely, Chen et al.³¹ reported even higher tear rates for CPCS, suggesting surgeon experience and procedure numbers as relevant factors. In the study with the largest sample, Schweiter et al.⁸ found that FLACS was precise but prone to incomplete capsulotomies, and had a similar anterior rupture rate to CPCS. Regarding posterior tears, FLACS reduced ultrasound use but extended surgery time, although there were no significant differences.

Postoperative complications

The incidence of macular edema did not differ significantly across the meta-analyses, which aligns with our findings.^9,10,12,40 Although corneal edema was not consistently mentioned, there were no significant difference 3 months post-surgery.

To the best of our knowledge, no meta-analysis has compared FLACS and CPCS specifically in terms of PCO, a complication that affects vision months to years after cataract surgery. Tran et al.⁴¹ reported fewer Neodymium:YAG capsulotomies with FLACS, suggesting reduced PCO. Yu et al.⁴² reported no PCO in FLACS, but cases in CPCS eyes. Other studies^15,28,30 have reported no significant PCO difference within 12 months, which is similar to our findings, suggesting that beyond-surgery factors influence PCO.

Other complications

Besides major risks, unique complications emerged. Suction loss, incomplete phacofragmentation, and nonperforated laser corneal incisions were noted by Schweitzer et al.⁸ in FLACS. Several RCTs^7,43 discussed decentered capsulotomies and IOL, with FLACS having fewer decentered cases. Major complications did not notably differ; however, minor complications warrant consideration.

Patient-reported outcome measurements

Besides efficacy and safety, quality of life is another important issue after cataract surgery, however, to the best of our knowledge, no meta-analyses have addressed these issues. To tackle this subject, we analyzed five studies that used PROMs as secondary endpoints.

Hansen et al.²⁷ and Liu et al.¹⁷ utilized custom questionnaires, delving into patient comfort, surgery duration, and visual outcomes for both FLACS and CPCS. Both studies found no discernible PROM differences between the two techniques. Interestingly, patients who received different surgeries in each eye favored FLACS over CPCS in the study reported by Hansen et al.²⁷ Meanwhile, Stanojcic et al.²⁸ and Roberts et al.²⁶ employed EQ-5D-3L, Cat-PROM5, and EQ-5D VAS scales, with Stanojcic et al.²⁶ revealing no significant PROM variance across the scales. In addition to using the EQ-5D-3L, Day et al.¹⁵ added Catquest-9SF for quality-adjusted life years (QALYs) calculation, revealing no notable differences between FLACS and CPCS after 12 months.

Categorizing data into patient-reported health, visual outcomes, and daily activity, our meta-analysis showed no significant PROM differences between FLACS and CPCS at all time points, except for short-term visual outcomes. Notably, visual PROM didn’t consistently match CDVA and UDVA results. In Liu’s study,¹⁷ the very short–term visual PROM even displayed contrasting outcomes with the UDVA results. Importantly, PROM results may be influenced by the type of IOL, which could not be analyzed in this study. Therefore, the findings should be interpreted with caution and are only for reference.

Laser subgroup analysis

Our comprehensive laser subgroup analysis evaluated five distinct laser platforms, revealing conflicting yet advantageous outcomes for each. Significant differences between groups were found in CDE, CCT, and ECL. Notably, significant reductions in CDE emerged with the Catalys, LenSx, and VICTUS systems. The LenSx platform also exhibited a notable decrease in CCT during FLACS, while the Catalys and LDV Z8 platforms demonstrated substantial ECL reductions. Remarkably, across all platforms, no significant differences were observed in CDVA, UDVA between CPCS and FLACS groups.

Despite differing technical specifications among platforms, variations seem primarily related to docking and mobility,⁴⁴ exerting a milder impact on effectiveness. However, unique strengths emerged for each platform. For instance, LDV Z8 stands as the sole approved platform for pediatric cataract surgery.⁴⁵ It is important to note that limited data and unidentified parameters for certain platforms may introduce biases. Further research is needed to comprehensively understand the impact of different laser platforms on cataract surgical outcomes.

Cost-effectiveness analysis

In terms of cost-effectiveness, Abell et al.⁴⁶ performed a retrospective comparative cost-effectiveness analysis, disclosing a cost of $92,862 Australian dollars per QALY under the assumption of a 5% improvement in visual acuity for FLACS. Regarding the productivity aspect, Roberts et al.⁴⁷ applied a “hub and spoke” model and concluded that even when operating under optimized circumstances, FLACS proved to be 8.7% more expensive than CPCS. Furthermore, the FACT study¹⁵ unveiled a mean QALY difference of 0.001 between the methods, which translated to an incremental cost-effectiveness ratio of £167,620. Moreover, the FEMCAT study⁸ established that the incremental cost-effectiveness ratio amounted to a saving of €10,703 for each additional patient who achieved treatment success with CPCS as opposed to FLACS. Consequently, FLACS has not been considered a cost-effective solution compared with CPCS.

While FLACS showed preliminary advantages in reducing EPT and CDE, the additional time for patient docking and laser application often increases the overall operative duration, especially for experienced surgeons.²⁷ This extended time, combined with higher instrument costs, generally makes FLACS not a cost-effective alternative to CPCS for routine cases. However, FLACS might offer benefits in specific challenging scenarios not fully captured in our meta-analysis, such as in very dense cataracts requiring less ultrasound energy or in eyes with corneal dysfunction where minimizing endothelial cell loss is critical.^32,48 Further targeted research is needed to definitively establish these advantages in particular clinical settings.

Surgery performed by a young surgeon

One proposed advantage of FLACS is its facilitation of crucial surgical steps such as capsulorhexis—a skill crucial for preventing complications that is often among the most challenging to master.⁴⁹ Studies exploring FLACS learning curves have indicated that approximately 25–30 cases are needed to achieve consistent results.⁵⁰ In this context, Hansen et al.²⁷ analyzed resident-performed surgeries and found nearly equivalent results in terms of postoperative visual acuity, ECL, patient satisfaction, and surgical complication rates. It is worth noting that the overall operative duration was increased due to the utilization of the laser. Similarly, Vasavada et al.¹⁶ reported that, in the context of junior surgeons, FLACS exhibited advantages over CPCS, manifesting as reduced intraoperative ultrasound energy dissipation and enhanced initial corneal clarity.

Limitations

Despite numerous advantages, our meta-analysis has limitations. Preoperative measurements, IOL power calculations, and IOL types influenced postoperative visual acuity, yet many studies didn’t specify the IOL used, hampering subgroup analysis. Varied follow-up times and complication assessment times introduced potential bias, though we mitigated this by categorizing and grouping. In addition, diverse patient-reported outcome questionnaires lacked standardization, adding bias. Unaccounted factors include cataract density and surgical settings due to limited reporting. Heterogeneity arose from regional differences, protocols, laser steps, surgical expertise, and reporting discrepancies. Addressing these is challenging due to variance and unreported parameters. Conversely, distinguishing older laser units from newer ones wasn’t feasible. In addition, none of the included RCTs specified pregnancy in their eligibility criteria; therefore, the present findings should not be extrapolated to pregnant patients. To overcome these limitations, further research exploring settings and challenges is recommended.

Conclusions

Our exhaustive meta-analysis and TSA unveiled preliminary advantages of FLACS in terms of CDVA, ECL, and CCT, coupled with statistically significant disparities in EPT and CDE. However, concerning extended-term and patient-centered outcomes, we observed no substantial disparities in visual acuity, complications, or patient-reported outcomes. Notably, our subgroup analysis suggested that each laser platform delivered consistent visual outcomes with potentially distinct surgical advantages. In summary, both techniques yielded comparable extended-term results encompassing visual outcomes, surgical efficacy, complications, and patient-reported outcomes. However, it is pivotal to note that FLACS does not emerge as a cost-effective alternative to CPCS.

Electronic supplementary material

Below is the link to the electronic supplementary material.

Author contributions

Conceptualization, C.-J.C.; methodology, C.-J.C. and J.-H.W.; software, S.-H.L., Y.-C.C., P.-C.T., and J.-H.W.; validation, C.-J.C. and J.-H.W.; formal analysis, S.-H.L., Y.-C.C., and P.-C.T.; investigation, S.-H.L., Y.-C.C., P.-C.T., and C.-J.C.; resources, C.-J.C. and J.-H.W.; data curation, S.-H.L., Y.-C.C., and P.-C.T.; writing—original draft preparation, S.-H.L., Y.-C.C., and P.-C.T.; writing—review and editing, C.-J.C. and J.-H.W.; visualization, S.-H.L., Y.-C.C., P.-C.T., J.-H.W., and C.-J.C.; supervision, C.-J.C. and J.-H.W.; project administration, C.-J.C. All authors have read and agreed to the published version of the manuscript.

Data availability

The datasets used and/or analyzed during the current study available from the corresponding author on reasonable request.

Declarations

Competing interests

The authors declare no competing interests.