الفهرس 
Phacoemulsification principleOnly 14 pages are availabe for public view
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Abstract
Over the years, there have been significant advances in cataract surgery and improvements are ongoing. Phaco-energy is still the main risk factor for surgically induced trauma especially on corneal endothelial cells. The aim of the recent phacoemulsification researches is to reduce phaco-energy and shorten the phaco time.
In our study, we compared two ultrasound modalities for phacoemulsification of hard nuclei, conventional and torsional ultrasound of the infiniti machine®. In the conventional ultrasound mode, the phaco tip moves forward and backward while the torsional ultrasound replaced the axial movement of a traditional phaco needle with the sideways oscillation of Kelman tip.
We found that torsional ultrasound was associated with shorter ultrasound time, cumulative dissipated energy than conventional ultrasound in hard nucleus phacoemulsification. Both techniques caused a significant decrease in endothelial count compared to preoperative count, there was a significant difference between them regarding the amount of endothelial cell loss being lower in the torsional group. The amount of postoperative increase in central corneal thickness was significantly lower in the torsional group at day 1 and day 7 but this difference became nonsignificant at one month.
In conclusion , Both ultrasound modalities can be used in hard nucleus phacoemulsification since there was no significant difference between them regarding the amount of increased corneal thickness at one month. However, the torsional ultrasound proved to be more safe since it was associated with lower endothelial cell loss and less increase in central corneal thickness in first day and first week postoperative and more effective since it was associated with lower ultrasound time and cumulative dissipated energy. The choice between these technologies is of particular importance when operating eyes with low endothelial cell count.