title: Analysis of a 23-gauge ultra high-speed cutter with duty cycle control.
abstract: OBJECTIVE
  The purpose of the study was to determine the performance of dual pneumatic ultra high-speed 23-gauge cutters operated with variable duty cycle (DC) settings.
  
  
  METHODS
  Frame-by-frame analysis of high-speed video was used to determine the DC in core, 50-50, and shave modes. Using three cutters at various cycles per minute and aspiration levels, mass of water or vitreous removed from a vial was measured within a specified time period. Average flow rates were calculated for each aspiration level and cut rate with the different DC options.
  
  
  RESULTS
  The DC increased with increasing cut rate in the shave mode was relatively stable in the 50-50 mode and decreased for the core mode. The DC converged at 5,000 cycles per minute for the 3 different modes. Water flow curves followed the DC variation. Vitreous flow rates for all the DC modes increased with increasing cut rates and peaked at 5,000 cycles per minute (P < 0.05). The results of the 50-50 mode, which had isolated the DC influence, showed that increasing aspiration and/or cut rate independently increased the vitreous flow rate.
  
  
  CONCLUSIONS
  Progressive values of aspiration and/or cut rate increase the vitreous flow rate, independently of the DC. The DC control also has an important effect on the vitreous flow, but this effect was reduced at high cut rates because of convergence of the DC modes.
authors: Doheny Eye Institute, Los Angeles, California, USA.
authors: Bruno
authors: B
authors: Diniz
authors: Rodrigo B
authors: RB
authors: Fernandes
authors: Ramiro M
authors: RM
authors: Ribeiro
authors: Jaw-Chyng
authors: JC
authors: Lue
authors: Anderson G
authors: AG
authors: Teixeira
authors: Octaviano
authors: O
authors: Magalhães
authors: Mauricio
authors: M
authors: Maia
authors: Mark S
authors: MS
authors: Humayun
mesh_terms: D000818:Animals; D008866:Microsurgery / Q000379:methods*; D013552:Swine; D014741:Video Recording; D014821:Vitrectomy / Q000295:instrumentation*; D014822:Vitreous Body / Q000601:surgery*; D014867:Water
chemical_list: D014867:Water