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Low-energy femtosecond laser-assisted IOL fragmentation shows feasibility
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BELGRADE, Serbia — Femtosecond laser-assisted IOL fragmentation using low energy parameters showed feasibility in a study presented at the European Society of Cataract and Refractive Surgeons winter meeting.
“There have been previous case reports, but the use of high energy and small spot produced excessive cavitation gas bubbles and production of toxic elements. Our purpose was to optimize energy parameters and verify the technique in the clinic,” Natalia Anisimova, MD, said.
Three hydrophobic lenses were previously dissected with variable energy between 1 µJ and 10 µJ with a laser spot and laser separation size of 7 µm. The effectiveness of femtosecond laser transection was evaluated with a score in which 1 was when transection lines were observed but the IOL could not be divided manually and 4 was when the IOL was fragmented without any mechanical force.
“We also observed with an optical microscope the changes produced by the laser on the surface and along the transection lines, and the formation of potentially toxic substances derived from the femtosecond laser energy interaction with the IOL material,” Anisimova said.
The 4 µJ to 6 µJ energy setting, with a spot of 7 µm, was judged to be safe, as no significant changes were observed. These parameters were used for IOL explantation in a patient with hyperopic error 2 months after cataract surgery. Hemidissection was performed with the laser, and a slight mechanical force was used to completely divide the lens, which was then explanted through a clear corneal incision.
Scanning electron microscopy showed small grooves and bumps of 6 µm to 25 µm, probably reflecting the application of laser pulses. At 6 months, no change in endothelial cell count was observed.
The femtosecond laser could facilitate and decrease the risks of IOL explantation, but further studies are need to assess the biocompatibility, quality and quantity of gas formation and the production of toxic elements.
“We also need to develop patterns to divide the IOL in smaller parts to decrease incision size,” Anisimova said. – by Michela Cimberle
Reference:
Anisimova N, et al. Femtosecond laser-assisted IOL fragmentation: low energy transection. Presented at European Society of Cataract and Refractive Surgeons winter meeting; Feb. 9-11, 2018; Belgrade, Serbia.
Disclosure: Anisimova reports no relevant financial disclosures.