Posters

In vitro thermal modifications induced by phacoemulsification, torsional phacoemulsification and photofragmentation: comparison of dynamic thermal signature, heat distribution and current patterns

Poster Details

First Author: P.Mattei USA

Co Author(s):    L. Toto   L. Vecchiarino   A. Merla   G. Di Marzio   L. Mastropasqua        

Abstract Details

Purpose:

To assess the differences in in vitro dynamic thermal signature, heat distribution and current patterns when using phacoemulsification, torsional phacoemulsification and photofragmentation observed with high speed thermal infrared imaging.

Setting:

Department of Ophthalmology, Università "G.d'Annunzio" of Chieti-Pescara, Italy

Methods:

Three systems that represent the three major methods for cataract removal were evaluated: 1. Whitestar Signature Phacoemulsification System with an Ellips FX handpiece (Abbott), 2. Constellation Vision System for torsional phacoemulsification (Alcon), and 3. Cetus Nanolaser System with a photofragmentation handpiece (A.R.C. Laser). A FLIR x8400sc thermal imaging system with an Indium Antimonide detector was used to acquire images at a resolution of 1280x1024 pixels at 106 Hz. Each handpiece dispersed an amount of energy equivalent to that required to complete a NOCS III grade 3 cataracts. Irrigation and aspiration were not used. Acquisition duration was standardized for analysis.

Results:

Torsional phacoemulsification produced the highest (70%) thermal increase, while phacoemulsification produced a 20% increase. Photofragmentation did not produce a thermal increase. The three between group differences were highly statistically significant (p<0.001) for all time points after 20% of the standardized procedure time, especially at the tip. Although photofragmentation handpiece does not have moving parts the laser pulse strikes a titanium plate positioned within the tip. This system is also the only one that did not produce harmonic summing of thermal effects at numerous points distant to the tip, representing areas of accumulated energy that could severely damage living tissue.

Conclusions:

The overall lower thermal modifications and the almost complete lack of harmonic accumulation of energy induced by photofragmentation should translate into a gentler cataract removal procedure. The torsional system was the most aggressive with significantly higher thermal modifications and areas of cumulative energy.

Financial Disclosure:

None