Phaco Fundamentals Part 5: Choosing Fluidic Parameters

Now that you have a good understanding of the principals of the fluidics involved in phaco surgery, let’s look at choosing specific parameters for each phaco mode. All of these suggested starting points are specific to the machine shown here (Alcon Centurion) and the specific 0.9 mm phaco tip / sleeve as well.

Please review the previous articles / videos about phaco fundamentals prior to proceeding here.

Do not use these suggested starting points as an absolute for your surgeries, rather understand the logic behind choosing them. This way you can set your specific machine to optimal settings for your specific style of surgery.

While I show many different modes here, remember that my normal, routine cataract surgery uses only three modes; chop, cortex, and visco removal settings.

Click below for a full explanation of each of these settings and parameters:


  1. Dear Dr Devgan,
    I’m a little confused here regarding Bottle height & Infusion pressure settings for various steps considering that modern machines have assisted infusion. Should changing the bottle height make any difference since there is air is being pumped into the bottle ? So at what ever height it is the infusion pressure would be the same. Secondly the other parameter you mention, infusion pressure. You keep it from 50 to as high as 80 during various modes. Why 50, considering normal IOP is about 20 why not keep there or just above it just to offset possible surge.

    1. Older phaco machines use just gravity to change infusion pressure (bottle height). Newer machines used a forced infusion such as pressure plates on a soft bag of BSS (Alcon centurion) or air pumped into the rigid glass bottle (B&L Stellaris). With these forced infusion machines there is not bottle height to set since gravity is not the primary factor. We work in a tiny space of just a few drops of fluid so too low of an infusion pressure will result in chamber instability. An infusion pressure of just 20 mmHg will be insufficient for the high flow / high vacuum techniques like phaco chop

  2. Hello, Prof. Devgan,
    Is there a reason you seem to use the purple sleeve rather than the smaller pink sleeve with the Centurion?

  3. Hi Professor Devgan. I have a Question. This parameters are set On the Alcon centurión wich is a peristaltic machine, I mostly use Stellaris PC/Elite for My routine cases, which parameters would you consider in that machine? Or You consider that this kind of parameters can be applied to B&L phaco machine too.

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