Alcon is conducting a voluntary medical device field safety corrective action for specific models of Constellation® UltraVit® (10k) and HyperVit® (20k) vitrectomy probe as there is potential for probes to unexpectedly fail to actuate and cut during use. There is a remote chance that an adverse event may occur if a probe unexpectedly fails to actuate and cut during surgery. Depending on the position of the cutter when the issue occurs and the amount of suction pressure applied by the probe, there is a potential for increased traction on the vitreous and/or retina that could lead to holes/tears.