Stability of a non-applanating handheld liquid patient interface for femtosecond laser-assisted cataract surgery

• Published in: International ophthalmology Vol. 40; no. 10; pp. 2683 - 2689
• Main Authors: Boden, Karl Thomas, Mariacher, Martina, Januschowski, Kai, Boden, Katrin, Rickmann, Annekatrin, Szurman, Peter, Seitz, Berthold, Mariacher, Siegfried
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01-10-2020
• Subjects: Medicine; Medicine & Public Health; Ophthalmology; Original Paper; Cataracts; Liquid patient interfaces; Laser-assisted cataract surgery; Break-away forces; FLACS
• ISSN: 0165-5701; 1573-2630
• DOI: 10.1007/s10792-020-01450-0

Purpose
A stable and reliable vacuum is crucial for the correct planning and performance of femtosecond laser-assisted cataract surgery (FLACS) in order to avoid complications such as suction loss and cyclorotation. This study investigates, for the first time, the impact of different vacuum levels on the stability of the application of a liquid patient interface for FLACS in view of break-away forces.
Methods
Break-away forces were measured using a multifunctional material testing machine with a mounted digital manometer. Sixteen porcine eyes were docked to the patient interface of a femtosecond laser platform (FEMTO LDV Z8), and the impact of different vacuum levels between 300 and 500 mbar investigated.
Results
Mean break-away forces for each vacuum level were as follows: 1.78 N (± 0.58 N) for 300 mbar; 2.24 N (± 0.68 N) for 350 mbar; 2.66 N (± 0.68 N) for 400 mbar; 2.86 N (± 0.77 N) for 420 mbar; and 3.49 N (± 0.86 N) for 500 mbar.
Conclusion
The stability increases with the vacuum in a nearly linear manner. Vacuum levels higher than 500 mmHg and lower than 350 mmHg are not recommended for FLACS.