Comparison of low-energy FLACS and conventional cataract surgery: meta-analysis and systematic review

TOPIC

To systematically compare the effectiveness of conventional phacoemulsification surgery (CPS) and low-energy femtosecond laser-assisted cataract surgery (FLACS) in patients with cataract.

CLINICAL RELEVANCE

Cataract surgery is a common procedure, and comparing different techniques such as CPS and low-energy FLACS is crucial for optimizing patient outcomes.

METHODS

The PubMed, Web of Science, MEDLINE, EMBASE, and Cochrane library databases were searched for clinical trials. Outcomes of procedure time, effective phacoemulsification time, balanced salt solution usage, cumulative dissipated energy, mean change of corrected distance visual acuity, endothelial cells reduction, central corneal thickness (CCT), and aqueous cytokine level were evaluated. The effect measures were weighted mean differences with 95% CI. The protocol was registered at the Prospective Register for Systematic Reviews (registration number CRD42023420173).

RESULTS

11 studies were included in this meta-analysis, of which 1680 eyes were analyzed (637 eyes in the low-energy FLACS group and 1043 eyes in the CPS group). Low-energy FLACS demonstrated significantly fewer reductions in endothelial cell count at 6 months ( P < .001) compared with CPS. It also exhibited a shorter effective phacoemulsification time ( P < .001) and less balanced salt solution usage ( P < .001). However, there were no differences in cumulative dissipated energy, corrected distance visual acuity, CCT changes, or aqueous cytokine levels between the 2 groups.

CONCLUSIONS

Both low-energy FLACS and CPS are effective in treating cataracts, but low-energy FLACS may offer advantages such as reduced phacoemulsification time and less endothelial cell loss.

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

Purpose

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

Methods

PubMed, Cochrane Library, and EMBASE were systematically searched for studies comparing FLACS and CPS. Outcomes were operative complications, including the intraoperative capsule tear, postoperative corneal edema, macular edema, uncontrolled IOP, etc. The effect measures were weighted with odds ratios with 95% CIs.

Results

Nineteen RCTs and 18 cohort studies, including 24,806 eyes (11,375 of the FLACS group and 13,431 of the CPS group), were identified. There were no significant differences between the two groups in anterior capsule tear, corneal edema, macular edema, uncontrolled IOP, vitreous loss, posterior vitreous detachment, etc. Posterior capsule tear rate showed a significantly lower in RCT subgroups (P ​= ​0.04) and without differences in total (P ​= ​0.63). Significant differences were observed in the incidence of descemet membrane tear/trauma (P ​= ​0.02) and IFIS/iris trauma (P ​= ​0.04. Additionally, The FLACS specific complications showed a significantly higher rate of miosis (P ​< ​0.0001), corneal epithelial defect (P ​= ​0.001), corneal haze (P ​= ​0.002), and subconjunctival hemorrhage (P ​= ​0.01).

Conclusions

FLACS maintains the same safety compared with CPS in terms of all intraoperative and postoperative complications. Although FLACS did show a statistically significant difference for several FLACS specific complications, it would not influence the visual outcome and heal itself.

Trifocal intraocular lens implantation in eyes with previous corneal refractive surgery for myopia and hyperopia

PURPOSE

To evaluate the visual and refractive outcomes of trifocal intraocular lens (IOL) implantation in eyes previously treated with myopic and hyperopic corneal refractive laser surgery.

SETTING

Clinica Baviera-AIER-Eye group, Spain.

DESIGN

Retrospective comparative case series.

METHODS

The series was divided into 2 groups according to the type of corneal laser refraction (myopic and hyperopic). The main visual and refractive outcome measures included corrected distance visual acuity (CDVA) and uncorrected distance and near visual acuity, safety, efficacy, and predictability. The secondary outcome measures were percentage of enhancement and Nd:YAG capsulotomy and influence of prelaser magnitude of myopia and hyperopia on the outcome of trifocal IOL implantation.

RESULTS

The sample comprised 868 eyes (543 patients): myopic, n = 319 eyes (36.7%); and hyperopic, n = 549 eyes (63.2%). Three months postoperatively, visual outcomes were poorer in the hyperopic group than those in the myopic group for mean CDVA (0.06 ± 0.05 vs 0.04 ± 0.04, P < .01) and safety (21% vs 12% of CDVA line loss, P < .05) outcomes. However, precision outcomes were worse in the myopic group than those in the hyperopic group, with a mean spherical equivalent of -0.38 ± 0.3 vs -0.17 ± 0.3 (P < .01). Stratification by magnitude of primary laser treatment revealed poorer visual and safety results in the high hyperopia subgroup (>+3.0 diopters [D]) and poorer precision in the high myopia subgroup (<-5.0 D).

CONCLUSIONS

Trifocal IOL implantation after photorefractive surgery in eyes previously treated with myopic ablation achieved good visual outcomes but less predictability in the high myopia subgroup. However, eyes with a previous hyperopic corneal ablation achieved excellent precision but worse visual and safety outcomes in the high hyperopia subgroup.

[Current value of femtosecond laser-assisted cataract surgery]

After more than 10 years of experience with the femtosecond laser in cataract surgery, it can be concluded that the safety profile of femtosecond laser-assisted cataract surgery (FLACS) is comparable to that of conventional cataract surgery. This technique offers the possibility to perform incisions with a precision superior to that of any surgeon in the world, based on the connection of preoperative and intraoperative diagnostics. This results in new possibilities to revolutionize the surgical procedure of cataract surgery and to generate new therapeutic approaches for the treatment of cataracts. The combination of keratotomy for correcting astigmatism, intraocular lenses supported by capsulotomy and individually adapted fragmentation patterns is already a component of a personalized cataract surgery.

Femtosecond laser-assisted cataract surgery: A review

PURPOSE

Review scientific literature concerning femtosecond laser-assisted cataract surgery.

METHODS

Following databases were searched: CENTRAL (Cochrane Eyes and Vision Trials Register; Cochrane Library: Issue 2 of 12, June 2019), Ovid MEDLINE^® without Revisions (1996 to June 2019), Ovid MEDLINE^® (1946 to June 2019), Ovid MEDLINE^® Daily Update June 2019, MEDLINE and MEDLINE Non-Indexed Items, Embase (1980-2019), Embase (1974 to June 2019), Ovid MEDLINE^® and Epub Ahead of Print, in-Process & Other Non-Indexed Citations and Daily (1946 to June 2019), Web of Science (all years), the metaRegister of Controlled Trials ( www.controlled-trials.com ), ClinicalTrials.gov ( www.clinicaltrial.gov ) and World Health Organization International Clinical Trials Registry Platform ( www.who.int/ictrp/search/en ). Search terms/keywords included 'Femtosecond laser' combined with 'cataract', 'cataract surgery'.

RESULTS

Based on quality of their methodology and their originality, 121 articles were reviewed, including randomised controlled trials, cohort studies, case-controlled studies, case series, case reports and laboratory studies. Each step of the femtosecond laser-assisted cataract surgery procedure (corneal incisions, arcuate keratotomies, capsulotomy and lens fragmentation) has been discussed with relevance to published outcomes, as well as complication rates of femtosecond laser-assisted cataract surgery, and what we can learn from the larger studies/meta-analyses and the economics of femtosecond laser-assisted cataract surgery within different healthcare settings.

CONCLUSION

Studies suggest that the current clinical outcomes of femtosecond laser-assisted cataract surgery are not different to conventional phacoemulsification surgery and it is not cost effective when compared with conventional phacoemulsification surgery. In its current technological form, it is a useful surgical tool in specific complex cataract scenarios, but its usage has not been shown to translate into better clinical outcomes.

Femtosecond laser-assisted versus phacoemulsification cataract surgery (FEMCAT): a multicentre participant-masked randomised superiority and cost-effectiveness trial

BACKGROUND

Cataract surgery is one of the most common operations in health care. Femtosecond laser-assisted cataract surgery (FLACS) enables more precise ocular incisions and lens fragmentation than does phacoemulsification cataract surgery (PCS). We hypothesised that FLACS might improve outcomes in cataract surgery compared with PCS despite having higher costs.

METHODS

We did a participant-masked randomised superiority clinical trial comparing FLACS and PCS in two parallel groups (permuted block randomisation stratified on centres via a centralised web-based application, allocation ratio 1:1, block size of 2 or 4 for unilateral cases and 2 or 6 for bilateral cases). Five French University Hospitals enrolled consecutive patients aged 22 years or older who were eligible for unilateral or bilateral cataract surgery. Participants, outcome assessors, and technicians carrying out examinations were masked to the surgical treatment allocation until the last follow-up visit and a sham laser procedure was set up for participants randomly assigned to the PCS arm. The primary clinical endpoint was the success rate of surgery, defined as a composite of four outcomes at a 3-month postoperative visit: absence of severe perioperative complication, a best-corrected visual acuity (BCVA) of 0·0 LogMAR (logarithm of the minimum angle of resolution) or better, an absolute refractive error of 0·75 dioptres or less, and unchanged postoperative corneal astigmatism power (≤0·5 dioptres) and axis (≤20°). The primary economic endpoint was the incremental cost per additional patient who had treatment success at 3 months. Primary outcomes were assessed in all randomly assigned patients who met all eligibility criteria (missing data considered as failure). We used mixed logistic regression models or mixed linear regression models for statistical comparisons, adjusted on centres and whether cataract surgery was bilateral or unilateral. The study is registered with ClinicalTrials.gov, NCT01982006.

FINDINGS

Of the 907 patients (1476 eyes) randomly assigned between Oct 9, 2013, and Oct 30, 2015, 870 (704 eyes in FLACS group and 685 eyes in the PCS group) were analysed. We identified no significant difference in the success rate of surgery between the FLACS and PCS groups (FLACS: 41·1% [289 eyes]; PCS: 43·6% [299 eyes]); adjusted odds ratio 0·85, 95% CI 0·64-1·12, p=0·250). The incremental cost-effectiveness ratio was €10 703 saved per additional patient who had treatment success with PCS compared with FLACS. We observed no severe adverse events during the femtosecond laser procedure, and most of the complications in the FLACS group related to the primary outcome measures occurred during the phacoemulsification phase or postoperatively.

INTERPRETATION

Despite its advanced technology, femtosecond laser was not superior to phacoemulsification in cataract surgery and, with higher costs, did not provide an additional benefit over phacoemulsification for patients or health-care systems.

FUNDING

French Ministry of Social Affairs and Health.

Comparison of Surgically Induced Astigmatism and Corneal Morphological Features Between Femtosecond Laser and Manual Clear Corneal Incisions

PURPOSE

To assess corneal morphologic changes and surgically induced astigmatism (SIA) following clear corneal incisions (CCIs) created manually or with the Catalys femtosecond laser (Johnson & Johnson Vision, Santa Ana, CA).

METHODS

In this retrospective cohort analysis, patients undergoing femtosecond laser-assisted cataract surgery (FLACS) or manual cataract surgery between June and September 2018 from a single surgical center in Toronto, Canada, were considered for inclusion. Postoperative corneal astigmatism values were compared to preoperative astigmatism indices to determine the SIA at the postoperative 3-month (POM3) mark using the Alpins vector method. Secondary outcomes included postoperative corrected distance visual acuity (CDVA), central corneal thickness (CCT), and CCI morphology parameters.

RESULTS

Refractive outcomes from 104 eyes of 61 patients (54 eyes in the manual group and 50 eyes in the FLACS group) were included. There was no significant difference in POM3 SIA (manual: 0.45 ± 0.28 diopters [D], FLACS: 0.57 ± 0.46 D, P = .11); however, a significantly larger SIA was noted in the FLACS cohort at postoperative 1 week (P = .02) and 1 month (P = .04). FLACS led to a significantly smaller POM3 CCI thickness (P = .006), and CCI position was comparable between the two techniques (P = .44). There were no significant differences between groups in CDVA (P = .19), CCT thickness (P = .20), or phacoemulsification time (P = .59).

CONCLUSIONS

There was no significant difference in SIA between FLACS and manual cataract surgery at POM3. With a significantly smaller CCI thickness seen in FLACS cases, and a comparable CCI position, the reason for the increased SIA following laser CCIs in the early postoperative period was unclear. [J Refract Surg. 2019;35(12):796-802.].