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Tighter femtosecond lens-softening grid reduces effective phaco time
Laser pre-treatment created small cubes of nuclear material that were easier to remove than larger pieces created with the manual technique.
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Femtosecond laser lens fragmentation with a smaller lens-softening grid significantly reduced ultrasound energy and phacoemulsification time, according to a study.
The study authors reported results obtained with the Catalys Precision Laser System (OptiMedica) in performing lens fragmentation in 350-μm and 500-μm grids.
“To our knowledge, this is the first study comparing the effect of ultrasound energy of different lens-softening grid patterns with a femtosecond laser for cataract surgery,” H. Burkhard Dick, MD, OSN Europe Edition Associate Editor and the corresponding study author, told Ocular Surgery News. “[This] shows that the Catalys system can virtually eliminate the use of ultrasound energy and that the smaller grid pattern is more effective in reducing ultrasound energy.”
Previous studies have shown that femtosecond laser-assisted cataract surgery involved less effective phacoemulsification time than standard manual lens fragmentation, Dick said.
“We have previously shown that a 500-μm grid reduces ultrasound energy by 96% compared with manual cataract surgery,” he said. “This study showed a further 86% reduction.”
H. Burkhard Dick
Study results were published in the Journal of Cataract and Refractive Surgery.
Patients and parameters
The prospective, randomized clinical trial included 160 eyes with senile cataract that underwent femtosecond laser-assisted cataract surgery. Capsulotomy and lens fragmentation were performed with the Catalys.
Lens-softening grid size was 350 μm in 80 eyes and 500 μm in 80 eyes.
The Stellaris phacoemulsification platform (Bausch + Lomb) was used to perform irrigation and aspiration through a 2.75-mm clear corneal incision.
Investigators used the Lens Opacities Classification System III (LOCS III) to grade cataract opacity preoperatively. Mean LOCS III grades were 3.7 in the 350-μm group and 3.5 in the 500-μm group; the difference was not statistically significant.
“At my institution, we are using an ‘all comers’ approach to the femtosecond laser,” Dick said. “In fact, the advantages of the laser are particularly important in difficult cases with harder lenses, loose zonules, etc. We have analyzed the data and have determined that the reduction in ultrasound energy from the manual approach to Catalys occurs across all LOCS grades we have treated.”
Outcomes and observations
Study results showed that mean laser treatment time was 66.4 seconds in the 350-μm group and 52.8 seconds in the 500-μm group.
Mean effective phaco time was 0.03 seconds in the 350-μm group and 0.21 seconds in the 500-μm group. Mean absolute phaco time was 2.05 seconds in the 350-μm group and 5.85 seconds in the 500-μm group. Both between-group differences were statistically significant.
The tighter lens-softening grid fragments the lens into smaller pieces that are easier to remove than pieces that are created with the larger grid, Dick said.
“The laser creates ‘french fry’ shapes, which, due to the lamellar structure of the lens, break into small cubes upon disassembly,” he said. “With the 350-μm spacing, these cubes are more easily aspirated than with the 500-μm grid, as these are less likely to get stuck in the phaco or irrigation-aspiration tip.”
No intraoperative or postoperative complications were reported during the 4-week follow-up. – by Matt Hasson