Anterior Vitrectomy Settings for Cortex Removal

Anterior vitrectomy settings for cortex removal depend on your phaco machine.

stellaris.  at our VA we use the stellaris where the cut on and off is controlled by the footswitch. with the stelarris, if you shift the footpedal to the side the cutter goes on or off (footpedal switches are programmable so your machine may be set differently).   as you push farther into the pedal you get more vacuum. the cut rate is fixed by the panel and is not controlled by the pedal. for the vitreous phase we use a vacuum setting of 150 and a max cut rate of 800. for the cortex phase we use the same vacuum but decrease the cut rate to 200.

infinity.  at our university we use the infinity which has 2 modes:  cut IA (used for vitreous removal) and IA cut (used for cortical removal). with the cut IA mode when you push farther into the pedal you get more vacuum but the cutter is on from the start-- thus called cut IA as the cutter comes on first. with the IA cut mode as you initially push into the pedal you get just the aspiration and then by pushing more into the pedal you eventually get the cutter on also -- thus called IA cut as the IA comes on first. for the vitreous phase we use a vacuum setting of 250 and a max cut rate of 800. for the cortex phase we use the same vacuum but decrease the cut rate to 200.

in general.  when removing cortical material you first make sure the vitreous is beaten back to the level of the posterior capsule. then turn the cutter off in the periphery and grab some anterior cortical material bring to the center and turn the cutter on while aspirating the cortical material. you turn the cutter on after bringing the cortical material into the center as you can never be too sure that you might not get some vitreous coming forward during aspiration and dont want to pull on the vitreous without cutting too. presumably you are less likely to encounter vitreous in the periphery when acquiring the cortex. titrate the bottle height so you are just able to maintain the chamber. make sure the cutter and irrigation are separate with a tight fitting wound (eg make a separate paracentsis for the cutter).