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Lens nucleus after grid pattern fragmentation with the VICTUS (Bausch + Lomb) femtosecond laser. Image from Zsolt Biro MD[/caption]
No ultrasound is necessary when using femtosecond laser-assisted cataract
surgery (FLACS) in most cataract patients, provided the correct nuclear fragmentation grid pattern is used, said Zsolt Biro MD, PhD, Head, Department of Ophthalmology, Medical University of Pécs, Hungary, and OPTIMUM Laser Centre, Budapest, Hungary.
“We postulate that, with the routine use of zero phaco, we can further reduce the damage to the endothelial cells and the macula, which results in better postoperative visual acuity and quicker rehabilitation of our patients,” Dr Biro told the XXXIV Congress of the ESCRS in Copenhagen, Denmark.
He noted that FLACS is gaining in popularity, not only because most of the important surgical steps can be performed with superb accuracy and repeatability. Furthermore, the perfectly circular and centred capsulotomies the laser provides allows for a more predictable and stable positioning of the intraocular lens (IOL), which is especially important for premium (multifocal and toric) IOLs.
Moreover, research has shown that the simpler nucleotomy patterns, such as the cross pattern or the so-called called “pizza pattern”, reduces the amount of phaco energy used by up to 50%. That in turn improves safety for the endothelium, reducing endothelial cell loss by up to 40%.
Furthermore, he noted that his own recent experience in a series of 20 patients shows that use of the cubicle grid nucleotomy pattern available with the VICTUS® (Bausch + Lomb) femtosecond laser platform can eliminate the need for ultrasound phacoemulsification completely in most patients.
“Zero phaco FLACS should result in clearer corneas on the first day,” added Dr Biro, President of the Hungarian Ophthalmological Society.
The cubicle grid pattern fragments the nucleus into tiny 400µm or 500µm cubes. After nucleofractis the small pieces can be successfully removed with the Bausch + Lomb 20-gauge zero phaco irrigation and aspiration handpiece through a 1.8-2.75mm clear corneal incision.
THE ROAD TO ZERO EPT
Dr Biro pointed out that effective phaco time (EPT) with standard ultrasound phacoemulsification can be as high as 10 to 12 seconds. With the earlier FLACS, EPT could be reduced to one second for grade I cataracts, between one second and two seconds for grade II cataracts, and between five seconds and six seconds for grade III cataracts.
He noted that his experience has shown that, with the cubicle grid nucleotomy pattern, zero phaco FLACS surgery is easy for grade I cataracts, a little bit difficult for grade II cataracts, a little bit more difficult still for grade III, and not successful for grade IV (LOCS III). He added that the learning curve is minimal.
When performing the zero phaco procedures, Dr Biro first locks the eye to the femtosecond laser and commences the nuclear fragmentation, using 500-micron cubicles in most cases. He noted that the fragmentation can be clearly observed in real time on both the surgical microscope and on the Victus system’s optical coherence tomography.
Following nucleofractis, he moves the patient a few feet over to the phacoemulsification suite. Dr Biro
then creates a 2.2mm clear corneal incision using a disposable knife. He then performs a hydrodissection and inserts the irrigation and aspiration handpiece and, with the vacuum set to 600mmHg, using a dual linear foot switch, and with the infusion bottle at 110-130cm, he extracts the fragmented nucleus and the cortex.
He cautioned that, although ultrasound is eliminated, the laser energy use can lead to bubble formation which might potentially lead to possible capsular rupture, increased levels of prostaglandin E2, intraoperative miosis, and potentially an increased inflammatory response.
The surgeon must also be careful to maintain anterior chamber stability
while removing the cataract, he noted. Fluid consumption with zero phaco can be 2.3 times higher on average than it is with conventional
FLACS. The higher fluid consumption causes fluid streams in the anterior chamber which has the potential to damage endothelial cells
and send small lens particles into
the vitreous.
“This was a descriptive analysis on a series of 20 cases without a research hypothesis. Further randomised trials are required to confirm the safety and efficacy of the zero-phaco technique of cataract removal,” Dr Biro concluded.