Comparison of torsional and longitudinal modes using phacoemulsification parameters
Received 2 February 2009; received in revised form 18 March 2009; accepted 16 April 2009.
Purpose
To compare phacoemulsification parameters of torsional and longitudinal ultrasound modes.
Setting
Ophthalmology Department, Military Health Service Institute, Warsaw, Poland.
Methods
This prospective study evaluated eyes 1, 7, and 30 days after phacoemulsification with an Infiniti Vision System using the torsional or longitudinal ultrasound (US) mode. Cataract classification was according to the Lens Opacities Classification System II. Nucleus fragmentation was by the phaco-chop and quick-chop methods. Primary outcome measures were phaco time, mean phaco power, mean torsional amplitude, and aspiration time. Total energy, defined as cumulative dissipated energy (CDE) × aspiration time, and the effective coefficient, defined as aspiration time/phaco time, were also calculated.
Results
Four hundred eyes were evaluated. The CDE was statistically significantly lower in the torsional mode for nucleus grades I, II, and III (P<.001) but not for grade IV (P>.05). Aspiration time was statistically significantly shorter in the torsional mode than in the longitudinal mode for nucleus grades III and IV (P<.05). Total energy was significantly lower in the torsional mode for all nucleus densities (P<.05). The effective coefficient was significantly lower in the longitudinal mode except for nucleus grade I (P<.05).
Conclusions
Torsional phacoemulsification was more effective than longitudinal phacoemulsification in the amount of applied fluid and the quantity of US energy expended. With the torsional method, it was possible to maintain a constant ratio of amount of fluid flow to quantity of US energy used, regardless of nucleus density.
From the Department of Ophthalmology (Rękas, Krix-Jachym, Kluś, Stankiewicz), Military Health Service Institute, Warsaw, Poland; the Optometry Research Group (Montés-Micó, Ferrer-Blasco), Optics Department, University of Valencia, Valencia, Spain
ABSTRACT