Comparison of sonic and ultrasonic phacoemulsification using the Staar Sonic Wave system

PURPOSE: To compare the performance of sonic phacoemulsification with that of ultrasonic phacoemulsification in regard to 1-day postoperative visual acuity, corneal edema, and procedure efficiency. SETTING: Oregon Eye Institute, Eugene, Oregon, USA. METHODS: This prospective nonrandomized study comprised 86 eyes with mild to moderate nuclear sclerotic cataract. Forty-three eyes had sonic and 43 ultrasonic phacoemulsification using the Staar Sonic Wave phacoemulsification system. The mean age was 76 years in the ultrasonic group and 71 years in the sonic group. The mean nuclear sclerosis was 2.0+ in the sonic group and 1.9+ in the ultrasonic group. Patient age, lens density, postoperative corneal edema, 1-day postoperative uncorrected visual acuity (UCVA), and the percentage of eyes with a visual acuity of 20/40 or better were determined. In addition, the mean ultrasonic and sonic times, mean percentage phaco power, and mean effective phaco time (EPT) were calculated in each group. RESULTS: Both groups had a 5% incidence of trace corneal edema. The mean UCVA was 20/41 in the ultrasonic group and 20/42 in the sonic group. Seventy-nine percent of eyes in the ultrasonic group and 74% in the sonic group had a UCVA of 20/40. The mean percentage phaco power was 7.2% and 7.6% in the ultrasonic group and sonic group, respectively. The mean EPT was low in both groups, 4.0 and 2.9 seconds, respectively. CONCLUSION: Sonic technology yielded outcomes similar to those of ultrasonic phacoemulsification with respect to postoperative visual acuity and corneal edema in patients with average density nuclear sclerotic cataract.