Review of phaco technology

Rosa Braga-Mele, MEd, MD, FRCSC, and co-author Panos Christakis, MD, conducted the review. The most difficult thing to analyze in such a study, Dr. Braga-Mele noted, is determining the parameters to compare because of the differences among the systems. She is associate professor, University of Toronto; director, cataract unit and surgical teaching, Mount Sinai Hospital, Toronto; and director of Research, Kensington Eye Institute, Toronto.

Ninety-eight patients who underwent phacoemulsification were included in the study: 31 for the Signature, 37 for the Infiniti, and 30 for the Stellaris. Dr. Braga-Mele performed all the procedures. The parameters recorded from video analysis and chart review were the total procedure time, total the phaco procedure time (tip-in to tip-out time), balanced saline solution (BSS) used, total phaco power, and repulsion, chatter events, turbulence, and followability evident on the video recordings.

The patients grouped by phaco system were well matched preoperatively for age, sex, and nuclear sclerotic cataract.

She said that the mean total phaco needle time differed significantly.

"The Stellaris System required less needle time in the eye, but this difference did not reach significance," she said. "This was followed by the Infiniti and the Signature system. However, with very dense nuclear cataracts, the Infiniti system significantly outperformed the other systems."

Regarding the mean total procedure time and the mean amount of BSS used, there were no differences among the machines.

Chatter evaluated

Evaluation of the chatter events on the surgical videos showed that the Infiniti system was associated with significantly less chatter compared with the Signature system; there was no difference in chatter between the Signature system and the Stellaris system. Compared with the Stellaris system, the Infiniti also had less chatter, likely because of the use of more non-longitudinal phaco and less longitudinal phaco, Dr. Braga-Mele said.

Followability was also better with the Infiniti machine, while the Stellaris trended toward better followability compared with the Signature machine for all cataract grades, she noted.

Stability was superior with the Infiniti machine compared with the other two machines, and the Stellaris system exceeded that of the Signature machine. There was no significant difference in stability between the Infiniti and Stellaris systems. In patients with low-density cataracts, the Stellaris surpassed the Infiniti and the Signature.

"The postoperative vision was significantly better with the Infiniti system compared with the other machines," Dr. Braga-Mele said. "In each phaco group, each case had significantly better postoperative vision compared with preoperatively."

The Infiniti machine had a lower increase in pachymetry compared with the Signature and the Stellaris, and there was no difference between the Signature system and the Stellaris system.

Data stratification for high-grade cataract showed no statistically significant difference between the Signature and the Infiniti machines but trended toward less increase in pachymetry for the Infiniti and no difference between the Signature and the Stellaris.

However, the Infiniti had a significantly lower mean increase in pachymetry than the Stellaris, Dr. Braga-Mele noted.

"All three phacoemulsification technologies were relatively similar," she said. "However, the Infiniti outperformed the other two machines with respect to less phaco needle time, increased followability and stability, less chatter, and less change in corneal pachymetry after surgery that resulted in better day 1 visual outcomes. This was especially true in cases with higher-density nuclear cataracts."

FYI

Rosa Braga-Mele, MEd, MD, FRCSC
E-mail: rbragamele@rogers.com

Dr. Braga-Mele is a consultant for Abbott Medical Optics, Alcon Laboratories, and Allergan. She was a consultant for Bausch + Lomb at the time this study was conducted. She presented these findings during the 2011 meeting of the American Society of Cataract and Refractive Surgery.