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FLACS on trial

The jury is still out on the benefits of femtosecond laser-assisted 
cataract surgery

Dermot McGrath

Posted: Friday, December 7, 2018


Zoltan Nagy MD

Femtosecond laser-assisted cataract surgery (FLACS) increases the safety and efficacy of cataract removal and results in more reliable and stable postoperative outcomes, according to Zoltan Nagy MD.
“FLACS advances an all-manual procedure to a precise, reproducible laser procedure. It improves certain key steps of cataract surgery such as corneal incision, capsulorhexis and lens fragmentation,” Dr Nagy told delegates attending a debate on the pros and cons of FLACS held during the World Ophthalmology Congress in Barcelona.
In traditional cataract surgery, capsulotomy size is directly related to effective lens position and corneal incisions are manually executed and can be imprecise, explained Dr Nagy.
“We also know that extensive phacoemulsification power is sometimes associated with corneal burn, corneal oedema and endothelial cell loss. Some studies show that cataract surgery complications are 10 times that of LASIK, ranging from common complications such as posterior capsule opacification (PCO), cystoid macular oedema, vitreous loss and endothelial cell loss up to vision-threatening complications such as retinal detachment and endophthalmitis,” he said.
Corneal incisions are not optimised in current cataract surgery and can result in astigmatism and infection, said Dr Nagy. The size and centration of the capsulorhexis also tends to be variable resulting in imprecise IOL position and lens power and may lead to problems of capsular tears and PCO. Excessive ultrasound power is used for lens fragmentation which can result in delayed visual recovery, loss of endothelial cells and capsular rupture, he added.
While FLACS increases the safety and efficacy of cataract removal, Dr Nagy said it will not replace traditional phacoemulsification.
“It will, however, replace the manually executed incision and capsulotomy steps and will effectively fragment the lens 
for more efficient lens removal. The ultimate goal of FLACS is to give the patient a premium surgical experience and the surgeon a procedure to be performed with confidence and predictability,” he concluded.
NO CLINICAL BENEFITS FOR PATIENTS?
Presenting the arguments against FLACS, Cédric Schweitzer MD said that while femtosecond technology is undoubtedly impressive there are currently no compelling arguments to justify investment in a femtosecond laser for cataract surgery.
“Femtosecond laser offers precise incisions associated with real-time imaging and clearly defined safety zones. It is very appealing technology but the reality is that this very precise cutting technology does not provide a meaningful difference in clinical outcomes for our patients,” he said.
The argument that FLACS leads to reduced intraoperative or postoperative complications does not really stand up to scrutiny, said Dr Schweitzer.
“If we look at posterior capsule rupture (PCR) which is the most common intraoperative complication of cataract surgery, a recent five-year audit study by Ti et al. of 48,377 phacoemulsification cases recorded 887 PCRs (1.8%). It is interesting to note that 60% of PCR cases occurred during the phacoemulsification stage, 25% during the irrigation-aspiration stage and 7% during IOL implantation. So, it is clear that FLACS cannot save all capsular rupture cases,” he said.
Another meta-analysis by Popovic et al in 2016 also found that PCR was actually more frequent in FLACS patients than those who underwent traditional phacoemulsification.
For postoperative endophthalmitis, an extensive French registry study by Creuzot-Garcher et al. of 6 million procedures from 2005 to 2014 showed a global decline of endophthalmitis cases from 0.145% to 0.053% related to the improvement in surgical procedure and intracameral antibiotic use, said Dr Schweitzer.
In terms of visual and refractive outcomes, a recent Cochrane meta-analysis by Day et al. reported a small advantage for FLACS at six months in corrected distance visual acuity (CDVA).
“The difference was not clinically significant and there was no difference found for uncorrected distance visual acuity,” said Dr Schweitzer.
Furthermore, the recent FEMCAT large-scale prospective, multi-centre French study of some 1,500 cases found no significant difference in terms of overall complication rates, best-corrected visual acuity (BCVA), mean absolute refractive error or postoperative changes in corneal astigmatism between FLACS and standard phacoemulsification, he added.
Summing up, Dr Schweitzer said despite the high precision of tissue cutting and safety, there is no evidence that FLACS improves health benefits for patients.
“It is more expensive and time consuming. It could, however, represent a new paradigm if there is further improvement in femtosecond laser innovation or association with other innovations in fluidics and new implant designs,” he said.
Zoltan Nagy: 
nagy.zoltan_zsolt@med.semmelweis-univ.hu
Cédric Schweitzer: 
cedric.schweitzer@chu-bordeaux.fr