DC control is important to vitreous flow

The variable duty cycle (DC) control on dual pneumatic ultra high-speed 23G cutters has an important effect on the vitreous flow but this is reduced at high cut rates as a result of convergence, reveals a paper in Retina.

Dr Bruno Diniz et al., Doheny Eye Institute, Los Angeles, California, USA, used frame-by-frame analysis of high-speed video to determine the DC in core, 50-50 and shave modes. The team used three cutters at various cycles per minute and aspiration levels, mass of water or vitreous removed from a vial was recorded within a certain time period.

For all three modes the DC converged at 5000 cycles per minute and water flow curves followed the DC variation. Vitreous flow rates for all DC modes increased along with the cut rates and peaked at 5000 cycles per minute. Vitreous flow rate independently increased when the DC influence was isolated and aspiration or the cut rate was increased.

Both progressive aspiration value and cut rate, either together or independently, increase the vitreous flow irrespective of the DC. Also, high cut rates reduce the significant effect the DC control has on the vitreous flow.

Please follow this link to read the abstract.