Evaluation of Cataract Lens Hardness Based on Phacoemulsificator Tip Resistance

The R-Evolution (Optikon 2000 Rome, Italy) phaco machine is equipped with a patented system named "minimal stress" that used the direct piezoelectric effect from the resonant ceramics that drive the phacoemulsificator tip to assess in real time and adjust phaco tip elongation that continuously varies according to encountered resistance.

After priming in balanced salt solution, phaco tip elongation and the amount of potential difference (voltage) needed to obtain a ginev elongation in balanced solution is assessed. Once the phaco tip is used during surgery, the resistence offered by the crystalline lens material to the phaco tip reduces actual elongaton which in turn reduces the voltage produced by the directo piezometric effect. The machine uses voltage produced by actual elongation to adjust the diving voltage and therefore can ensure accurate pahco tip elongation under any condition of lens material resistance.

Purpose of the study is to record driving voltage and its variations and evaluate if there is a correlation between phaco tip resistence and drving voltage.

This is evaluated both in vitro activating the phaco tip in increasingly dense glycerol solutions and in real life phaco surgery recording the voltage requested by phaco tip resistence and correlating it to the classification of lens opacity (LOCS III system) clinically used to grade cataract hardness.