Thermal effect of microburst and hyperpulse settings during sleeveless bimanual phacoemulsification with advanced power modulations.
OBJECTIVE
To assess wound temperature during bimanual sleeveless phacoemulsification using customizable power modulations such as hyperpulse and microburst technology.


METHODS
In vitro laboratory.


METHODS
The Millennium Microsurgical System (Bausch & Lomb) with custom control software (CCS) was used to perform phacoemulsification in 5 porcine eyes with MicroFlow needles (Bausch & Lomb) and with power varied from 20% to 80% in 10% increments. Pulse modes were set for fixed microburst (4 ms on, 4 ms off; and 6 ms on, 12 or 24 ms off) and for hyperpulse (30% duty cycle with 8 or 75 pulses per second [pps]), with and without aspiration-line occlusion. Wound temperatures were measured 3 times per second.


RESULTS
Using 80% total power, the wound temperature during 3 minutes of occlusion did not exceed 39.0 degrees C. The maximum temperature with fixed microbursts of 4 ms on, 4 ms off was 29.0 degrees C without occlusion and 37.8 degrees C with occlusion (duration 3 minutes). At 6 ms on, 12 ms off, the maximum temperatures were 28.1 degrees C and 38.7 degrees C, respectively. At 6 ms on, 24 ms off, peak temperatures were 24 degrees C and 23.6 degrees C, respectively. The hyperpulse mode of 30% duty cycle and 8 pps produced maximum temperatures of 25.5 degrees C nonoccluded and 33.4 degrees C occluded. With 30% duty cycle, 75 pps, temperatures were 28 degrees C and 38.0 degrees C, respectively. For all power below 80%, temperatures were lower.


CONCLUSIONS
Customizable power modulation with microburst and hyperpulse technology further reduced wound temperatures during bimanual sleeveless phacoemulsification. This enhances the safety and effectiveness of phacoemulsification through a sleeveless needle and a small stab incision.
Braga-Mele
Rosa
R
Department of Ophthalmology, University of Toronto, Toronto, Canada. rbragamele@rogers.com
D000818:Animals; D000869:Anterior Eye Segment / Q000293:injuries* / Q000503:physiopathology; D001831:Body Temperature; D005126:Eye Burns / Q000503:physiopathology*; D006358:Hot Temperature; D018918:Phacoemulsification / Q000379:methods*; D013552:Swine; D013997:Time Factors