To compare the clinical outcomes during phacoemulsification when using recently improved longitudinal (Stellaris®, Bausch & Lomb, Rochester, NY, USA) and torsional (Infiniti Ozil®, Alcon, Fort Worth, TX, USA) ultrasound.

The present study included 74 eyes of 59 patients undergoing cataract surgery. Operated eyes with mild cataract (nuclear sclerosis grade 1 and 2), moderate cataract (nuclear sclerosis grade 3) and hard cataract (nuclear sclerosis grade 4 and 5) were compared in terms of the total phacoemulsification (phaco) time, average phaco power, total phaco energy and amount of fluid used during cataract surgery between the 2 modalities. Endothelial cell density, corneal edema, central corneal thickness (CCT), surgically induced astigmatism (SIA) and best-corrected visual acuity (BCVA) were also evaluated preoperatively and up to 3 month postoperatively.

In mild cataracts, the operative parameters and corneal changes were similar between the 2 modalities. In moderate cataracts, the total phaco time was significantly higher in the torsional group than the longitudinal group, but the average phaco power, total phaco energy, and amount of fluid were not significantly different. In patients with hard cataract, the torsional group showed higher total phaco time (27.50 ± 17.77 sec vs. 97.08 ± 12.67 sec), average phaco power, total phaco energy, persistent corneal edema at 1 week postoperatively and more endothelial cell loss at 3 month postoperatively (16.33 ± 15.50% vs. 38.71 ± 26.49%). Postoperative CCT, SIA and BCVA were not significantly different in hard cataracts between the 2 modalities.

In mild and moderate cataracts, the efficiency of phaco and corneal changes were similar between the 2 modalities. However, recently improved longitudinal phaco showed superior efficiency for hard cataracts and induced less endothelial cell loss than torsional phaco.