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.
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.
Authors: Bruno Diniz; Ramiro M Ribeiro; Rodrigo B Fernandes; Jaw-Chyng Lue; Anderson G Teixeira; Mauricio Maia; Mark S Humayun Journal: Ophthalmologica Date: 2012-10-27 Impact factor: 3.250