Heat profiling of phacoemulsification tip using a thermal scanning camera

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ORIGINAL PAPER

Heat profiling of phacoemulsification tip using a thermal scanning camera Wei Kiong Ngo • Louis W. Lim • Colin S. H. Tan • Wee Jin Heng

Received: 5 September 2012 / Accepted: 1 March 2013 / Published online: 20 March 2013 Ó Springer Science+Business Media Dordrecht 2013

Abstract An experimental study to measure the heat profile of the phacoemulsification (phaco) tip using standard continuous phaco and hyperpulse phaco with and without waveform power modulation in the Millennium Microsurgical System with Custom Control Software (CCS). The phaco tip was imaged in air using a thermal camera. The highest temperature was measured 15 s after application of phaco power. Continuous, hyperpulse and waveform power modulations of the Millennium Microsurgical System were used with different power settings (20, 50 and 100 %) and duty cycles (40, 60 and 90 %), with the irrigation turned on and off. Using continuous phaco with the irrigation on, the phaco tip temperature remains \28.0 °C. With irrigation off, the temperature is higher compared to irrigation on but still remains \45.0 °C. Comparing the temperatures for all three power modulations when irrigation is on, at each phaco power and duty cycle setting, the temperature of the phaco tip is highest with continuous phaco, followed by hyperpulse with rise time 1, then hyperpulse with rise time 2. When irrigation is off, the W. K. Ngo  C. S. H. Tan  W. J. Heng (&) Department of Ophthalmology, Tan Tock Seng Hospital, Singapore, Singapore e-mail: [email protected] W. K. Ngo  L. W. Lim  C. S. H. Tan  W. J. Heng National Healthcare Group Eye Institute, Tan Tock Seng Hospital, 11 Jalan Tan Tock Seng, Singapore 308433, Singapore

highest temperatures are recorded using the hyperpulse with rise time 2, followed by continuous phaco, then hyperpulse with rise time 1. Hyperpulse and waveform modulations reduce heat generation compared to the continuous mode when irrigation is turned on. Lower duty cycles and lower ultrasound power produce less heat at the phaco tip. Keywords Phacoemulsification  Wound temperature  Cornea  Wound burn  Phaco tip

Introduction Thermal injury to the cornea occurs during phacoemulsification (phaco) when there is inadequate flow of irrigating fluid around the phaco tip to dissipate the heat generated by friction between the vibrating phaco probe and the infusion sleeve [1]. The amount of phaco (ultrasound) power used is an important factor in heat generation. Manufacturers of phaco machines have utilized new technologies to lower the total ultrasound power used in order to reduce the risk of phaco wound burn and endothelial damage. However, it has not been demonstrated that these technologies result in less heat generated compared to conventional phaco. Our study aimed to measure the heat profile of the phaco tip using standard continuous phaco and hyperpulse phaco with and without waveform power modulation in the Millennium Microsurgical System

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Int Ophthalmol (2013) 33:645–649

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