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Daniele Tognetto MD, Pia Leon MD,Paolo Cecchini MD, Silvia Rinaldi MD, Giuseppe Ravalico MD
The Authors have no proprietary interest in any products or devices discussed in this presentation
University Eye Clinic of Trieste (Italy)Head: Prof. Giuseppe Ravalico
Phaco Tip Displacement and Working Frequencies of different Phaco Machines
Aim of the study:
Step 1. determine the working frequency of the phaco machines
Step 2. evaluate the extent of the longitudinal stroke of the phaco machines
Step 3. analyze the shape and the dynamics of the stroke of two phaco machines working with lateral tip movements
AMO Signature Ellips FX
Alcon Infiniti Ozyl Torsional
Bausch&LombStellaris
Phaco machines analyzed
Step 1- Working frequencyVideo wet stroke fixture
Transparent BSS filled chamber
High magnification videocamera
Micrometric fixture
Strobo light source
Phaco handpiece
PHACO MACHINE Working FrequencyAlcon Infiniti OZil
Longitudinal 43.61 Hz
Torsional 31.62 Hz
Abbott Signature Whitestar
Ellips longitudinal 29.05 Hz
Ellips FX 38.00 Hz
Baush&Lomb Stellaris 28.75 Hz
Step 1- Results Working frequency
x y
y
x
Camera
Step 2 -Tip dynamics Video wet stroke fixture
Transparent BSS filled chamber
High magnification videocamera
Micrometric video controller
X and Y superimposed measurement lines
External peristaltic pump
Light source
A shiny spot is used as a surface landmark which generates a visible trace varying in shape and length according to the tip movement
Phaco handpiece
Longitudinal tip movement at rising phaco power
Step 2 - Results U/S Longitudinal
AMO Signature Ellips FX
Alcon Infiniti OZil Torsional
■ X and Y components of tip movement■ Different power settings (10 to 100%)■ Bent tip (end of tip and at incision)
Side-to-side movement is an emerging phaco technology and an effective alternative
to conventional lungitudinal U/S
Step 3 – New phaco modalities
Longitudinal and lateral movement at rising phaco power
Infiniti Ozil- Virtually no longitudinal movement- Linear increase at rising power
Ellips FX- Both longitudinal and lateral components, drawing an elliptic pattern- Linear increase of movement up to about 40% then tending to a plateau
Step 3 Results – New phaco modalities
Reduced movement at incision for both machines (especially for Alcon OZil)
Alcon OZil
A single movement variable was mathematically calculated from longitudinal and lateral movement taking into account the working frequency
Infiniti OZil: Linear increase of stroke
Ellips FX: Linear increase to about 40% then tending to a plateau
Step 3 Results – Normalized stroke
CONCLUSIONS
Step 1 - Working Frequency
The knowledge of the working frequency is important to compare
the different machines in terms of delivered phaco energy
Step 2 - U/S Longitudinal
A different movement behaviour has been observed
■ Alcon Infiniti: highest frequency, lowest stroke extension■ AMO Signature: lower frequency, higher stroke extension■ Bausch&Lomb Stellaris: lower frequency, highest stroke
exstension
CONCLUSIONS
Step 3 - Torsional and transversal mode
■ Infiniti OZil: - Horizontal stroke with linear power delivery
- Longitudinal stroke almost absent
■ Ellips FX: - Mostly horizontal stroke up to 40%- Mostly longitudinal stroke tending to a
plateau over 40% power
The stroke dynamic is an important variable affecting phaco cutting efficiency
Its knowledge is crucial to exploit the advantages of these new phaco devices