A Novel Ultrasound Modality Versus Torsional Ultrasound: Comparison Of Total Energy And Efficiency

4D Phaco (4D) volumetric ultrasound (US) was developed as part of UNITY VCS/CS. This
study compares phacoemulsification efficiency and energy of two US modalities: volumetric vs torsional
(Tors) and tip design with 4D: hybrid vs balanced.

Experimental bench-top and surgical simulation; Alcon Research, Ltd., Lake
Forest, California, USA

15 artificial Kitaro lenses (simulating LOCS III/NO4/NC4/P1/C1 cataract) were emulsified
with balanced tip using Tors and 4D. In both groups, US power, vacuum, IOP, and aspiration were set to
60% fixed, 450mmHg, 55mmHg, and 40cc/min, respectively. Additional 42 Kitaro lenses were weighed
and emulsified with hybrid and balanced tips at 60% fixed 4D US power, 550mmHg vacuum, 38mmHg
IOP and 38cc/min aspiration to evaluate difference in efficiency and energy dissipation between tips. US
time, energy (Joules) and cumulative dissipated energy (CDE) were evaluated for all tested conditions.

Compared to Tors, 4D demonstrated better efficiency across measured metrics with balanced
tip, including mean aspiration volume by 26% (14.20±3.76 vs 19.20±5.66cc, p<0.01), aspiration time by
35% (37.07±8.18 vs 56.93±14.85s, p<0.0001), and US time by 52% (20.81±6.57 vs 43.35±13.47s,
p<0.0001). 4D showed a 52% reduction in energy delivered into the eye (27.47±8.70 vs 57.63±17.89J,
p<0.0001) and 52% reduction in energy dissipated at the incision (CDE, 4.99±1.58 vs 10.40±3.23,
p<0.0001). Using 4D, hybrid tip required significantly less energy (Joules/mg) compared to balanced tip
by 36% (0.43±0.10 vs 0.70±0.15J/mg, p<0.0001).

UNITY VCS/CS’s 4D Phaco is more efficient and reduces US energy vs torsional,
which may translate to less postop corneal edema and quicker visual recovery. Higher efficiency with 4D
Phaco may allow use of hybrid tip in dense cataracts.