A new vitreous cutter blade engineered for constant flow vitrectomy.

The standard guillotine-shaped vitreous cutter blade (hereafter named Regular Blade [RB]) did not substantially change over the past 40 years, because of its simple and robust design. The asynchronous suction and cutting action, typical of RB blades, determines complete port obstruction generating flow instability and fluid acceleration that results in limited efficiency and eventually retinal traction. Newer blade shapes allowing residual flow when the port is “closed,” have been recently described and shown to yield a more favorable duty cycle, fluid dynamics, and volumetric flow rate. We herein introduce a further improvement of blade design, named Constant Flow Blade (CFB; Twedge Cutter Blade; Optikon 2000 Inc, Rome, Italy), that maintains the amount of open port surface invariant throughout the duty cycle, achieving a much higher flow while doubling cut rate. Description