Guillotine performance: duty cycle analysis of vitrectomy systems
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Published on: June 14, 2021
Octaviano Magalhaes1, Lawrence Chong, Charles DeBoer
1From *Eye Concepts, Doheny Retina Institute, Doheny Eye Institute, Los Angeles, California; †Paulista School of Medicine, Federal University of São Paulo, Brazil; and ‡Department of Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles.
Purpose:
To evaluate the duty cycle of different vitrectomy cutters and classify their blade movement.
Methods:
A precise weighing (0.01 g) high speed (2 samples/s) balance was used to study the 20-gauge and 25-gauge Bausch & Lomb Lightning-Millenium (St. Louis, MO), the 20-gauge (1500 cpm) and the 25-gauge Alcon Accurus (Fort Worth, TX), the 20-gauge Alcon Innovit, and the 23-gauge DORC (Netherlands) cutters. The weight of balanced saline solution (BSS) was recorded in real time using LabView software and then translated into a graph of volume removed versus time. Variable cut rates and vacuum pressures were analyzed in vitreous and BSS. A high-speed (400 frames/s) camera was used to record cutting for each condition.
Results:
Three types of duty cycle were investigated: parabolic incomplete (pneumatic), sinusoid (electric), and trapezoid (double pneumatic). The parabolic incomplete and trapezoid had a decreased duty cycle at 1500 cuts per minute when it was compared to 600 cuts per minute. The sinusoid had no statistical difference between cut rates.
Conclusions:
Systems showed different performances of duty cycle. This new classification will be useful for improved understanding of vitrectomy in these different systems.
