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Redefining the optimal frequency for more efficient phacoemulsification: a randomised controlled trial comparing different ultrasound frequencies for phacoemulsification

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Session Details

Session Title: Cataract Surgery Equipment/Instrumentation/Surgical Devices

Session Date/Time: Monday 09/10/2017 | 16:30-18:00

Paper Time: 16:59

Venue: Room 4.4

First Author: : T.Dewan INDIA

Co Author(s): :    P. Malik   R. Kumari                 

Abstract Details


To compare the effective phaco time using two different frequency handpieces of the same machine for phacoemulsification of immature senile cataract (grade 4.0 to 6.9) and to compare corneal endothelial safety between the groups over one year follow up. This randomised controlled trial intended to selectively elucidate the role of the ultrasonic frequency not just on peroperative performance but also on endothelial health postoperatively. Owing to lack of comparability between different machines, two different frequency handpieces on the same machine were used for longitudinal phacoemulsification to avoid potential confounding effect of unique phacodynamics of different machines.


The study was conducted at Department of Ophthalmology, Post Graduate Institute of Medical Education and Research & Dr Ram Manohar Lohia Hospital, New Delhi, India


160 consenting patients of grade 4.0-6.9 senile cataract were randomized into two groups for phacoemulsification: Group A- low frequency phacoemulsification (28 KHz) and Group B- high frequency phacoemulsification(42 KHz) on Megatron S3 (Geuder, Heidelberg, Germany) Effective Phaco Time(EPT) and fluid usage were compared peroperatively. The endothelial parameters were followed up postoperatively for one year. A comparison of endothelial status as well as percentage losses was done over the entire follow up. The same was also analysed after excluding the effect of age, nuclear grade, EPT and fluid usage to find any independent effect of frequency on the endothelium.


158 patients completed the study. Both the groups were comparable for age, gender, grade of cataract and baseline endothelial cell counts. Peroperative analysis revealed significantly lower EPT (p=0.008) and Fluid usage (p=0.004) in the higher frequency group. Postoperatively endothelial studies showed higher frequency group had significantly better endothelial cell density at 1,3,6,9 and 12mths (p<0.05). This was also clearly reflected by significantly lower percentage losses at the same follow up periods (p<0.05). The same persisted even after adjusting for age, grade, EPT and Fluid usage indicating salvaging effect of higher frequency over endothelium


Higher frequency ultrasound is more effective as well as safer than lower frequency in moderate to hard cataracts. We postulate that the lower EPT might be due to our reaching closer to the optimal frequency required for tackling these cataracts. The endothelium sparing effect of the same might be due to more localized action of higher frequency. The study clearly opens up new horizons for refining phacoemulsification technology.

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