Torsional mode versus conventional ultrasound mode phacoemulsification: Randomized comparative clinical study

Accepted 15 October 2006.

Purpose

To compare the intraoperative and short-term postoperative outcomes of cataract surgery performed with torsional mode and conventional ultrasound mode using the Infiniti Vision System (Alcon Laboratories).

Setting

Cataract Service, Zhongshan Ophthalmic Center, Sun-Yat-Sen University, Guangzhou, China.

Methods

In this randomized comparative study, 525 eyes were assigned to phacoemulsification by torsional mode or conventional ultrasound (US) mode. The surgery was performed by an experienced surgeon, and the outcomes were evaluated by an examiner who was masked to treatment assignments. Primary outcome measures were US time (UST), cumulative dissipated energy (CDE), and surgical complications. Patients were seen 1, 7, and 30 days after surgery. Postoperative outcome measures were the final best corrected visual acuity (BCVA) and the change in corneal clarity, central corneal thickness (CCT), and endothelial cell count.

Results

The US group had 262 eyes and the torsional group, 263 eyes. All patients completed the follow-up visits. In the eyes with nucleus density grades of 1, 2, 3, and 4, the mean UST was 10.25 seconds ± 7.4 (SD), 25.14 ± 5.5 seconds, 36.45 ± 8.3 seconds, and 61.44 ± 17.8, respectively, in the US group and 8.32 ± 6.8 seconds, 18.45 ± 7.2 seconds, 29.48 ± 12.4 seconds, and 48.39 ± 20.3 seconds, respectively, in the torsional group (P<.001); the mean CDE was 1.25 ± 0.5, 4.18 ± 1.2, 8.59 ± 6.5, and 16.51 ± 9.6, respectively, in the US group and 0.94 ± 0.3, 3.13 ± 2.7, 7.47 ± 12.6, and 14.08 ± 8.3, respectively, in the torsional group (P<.001). At 1 day and 7 days, the mean BCVA was 0.23 ± 0.12 logMAR and 0.00 ± 0.10 logMAR, respectively, in the US group and 0.18 ± 0.11 logMAR and −0.08 ± 0.05 logMAR, respectively, in the torsional group (P<.001). At 30 days, the mean BCVA was −0.10 ± 0.07 logMAR and −0.12 ± 0.06 logMAR in the US group and the torsional group, respectively (P>.01). At 1 day and 7 days, the mean CCT was 625 ± 80 μm and 568 ± 37 μm, respectively, in the US group and 601 ± 35 μm and 559 ± 40 μm, respectively, in the torsional group (P<.001). At 30 days, the mean CCT was 531 ± 30 μm in the US group and 529 ± 39 μm in the torsional group (P>.01). At 7 days and 30 days, the mean central corneal endothelial cell count was 2135 ± 858 cells/mm2 and 2084 ± 527 cells/mm2, respectively, in the US group and 2004 ± 656 cells/mm2 and 1953 ± 615 cells/mm2, respectively, in the torsional group (P<.001).

Conclusion

The torsional mode may provide more effective lens removal with a lower level of phacoemulsification time and energy.

From the Zhongshan Ophthalmic Center (Y. Liu, M. Zeng, X. Liu, Luo, Yuan, Xia, Zeng), the Key Laboratory of Ophthalmology (Y. Liu, Zeng, X. Liu, Luo, Yuan, Xia, Zeng), Zhongshan Ophthalmic Center, Sun-Yat-Sen University, and the Second Hospital of Guangzhou Medical College (Zeng), Guangzhou, China

Corresponding author: Yizhi Liu, MD, PhD, Zhongshan Ophthalmic Center, Sun-Yat-Sen University, Guangzhou 510060, China.

No author has a financial or proprietary interest in any material or method mentioned.

Y. Liu and M. Zeng contributed equally to this work.

Presented in part at the 21st Congress of the Asia-Pacific Academy of Ophthalmology, Singapore, June 2006.

PII: S0886-3350(06)01472-6

doi:10.1016/j.jcrs.2006.10.044

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