Reduced phaco time observed with use of oscillation device

September 1, 2008

Use of an oscillation device (NeoSoniX handpiece, Alcon Laboratories) results in a shorter phacoemulsification time compared with the time in cases in which a conventional handpiece was used. This difference may result in less phaco energy use in the eye, less trauma during surgery, more rapid visual rehabilitation postoperatively, and perhaps less loss of endothelial cells.

Key Points

Chicago-Use of an oscillation device (NeoSoniX handpiece, Alcon Laboratories) results in a shorter phacoemulsification time compared with the time in cases in which a conventional handpiece was used. This difference may result in less phaco energy use in the eye, less trauma during surgery, more rapid visual rehabilitation postoperatively, and perhaps less loss of endothelial cells, reported Jin Choi, MD, at the annual meeting of the American Society of Cataract and Refractive Surgery.

"Many surgeons have attempted to reduce the amount of ultrasound energy in the eye during phacoemulsification because of heat and cavitational effects," said Dr. Choi, who is affiliated with the Department of Ophthalmology, Catholic University of Korea, Seoul. "The handpiece features traditional longitudinal ultrasonic vibration amplitudes with a component of ±2° on both sides and 100 non-linear oscillations per minute generated by an electric motor.

Study purpose

The study included 67 eyes of 61 patients, all with dense nuclear cataracts evaluated before surgery.

Patients were randomly divided into two groups: one group treated with phaco and the oscillation device, and the other treated with phaco and a conventional ultrasound handpiece. In the group in which the oscillation device was used, the oscillation was fixed at 100%.

All surgeries were performed by the same surgeon with a phacoemulsification system (Infiniti, Alcon Laboratories). Lens densities were measured preoperatively using a Scheimpflug camera (EAS-1000, Nidek).

Dr. Choi and colleagues evaluated the phaco energy used, mean time of surgery, and effective phaco time between the two groups. They also evaluated the effect of lens thickness and the phaco time in the group in which the oscillation device was used.

"There was no significant difference in the mean patient age or cataract density between the two groups," Dr. Choi said. "The mean phaco time in the [oscillatory handpiece] group was significantly shorter (p = 0.018) compared with the conventional handpiece group (28 versus 49 seconds, respectively). The effective phaco time in the [oscillation device] group was about half of that in the conventional handpiece group (p <0.05).

"In addition, the amount of ophthalmic viscoelastic device used during the surgery did not differ significantly between the two groups," Dr. Choi said.

Evaluation of the correlation between the lens densities and the phaco time measured preoperatively in the oscillation device group showed a significant correlation between the cortical and nuclear densities and the phaco time.

"Use of the handpiece results in significantly lower average phaco time and lower effective phaco time compared with a conventional handpiece, especially in emulsification of dense cataract," he said. "Introduction of the oscillation tip motion in coordination with power modulation permits further reduction in total ultrasonic energy and performance of safer surgery.

"In addition, the cortical and nuclear densities were related significantly to the phaco time," he concluded.

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