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A dual-linear phacoemulsification platform (available on the Stellaris, Bausch & Lomb) separates phaco and vacuum, allowing cataract surgeons to maximize their control over the cataract removal procedure.
"The freedom of completely separating vacuum/aspiration from phaco is kind of a macrocosmic jump in the way we do phaco," said Dr. Whitman, a private practitioner at Key-Whitman Eye Center, Dallas. "It's really a different mindset. You don't know it until you've separated the two that, often, all you really need to remove the lens is vacuum."
In addition to on-demand independent linear control of aspiration and phaco power, the dual-linear technology includes programmable foot pedal settings that can be customized to the practitioner's preferences, according to Dr. Whitman.
Study of 37 eyes
Dr. Whitman performed standard phaco surgery on 37 eyes in his practice using the same phaco machine. Eighteen eyes were treated with the machine equipped with the dual-linear technology, whereas in 19 eyes the cataract was removed using the single-linear foot pedal.
Gender mix, mean age, and mean cataract densities (2 on a scale of 1 to 4) were similar in both groups.
He said he observed that mean phaco power was lower (4.4%) in the dual-linear group than in the single-linear group (6.7%). Mean phaco time was higher in the dual-linear group (16.2 seconds) than in the single-linear group (12.7 seconds).
The mean effective phaco time (EPT) as a function of time of phaco on was identical in both groups, at 0.92 seconds, he said.
"Overall, it takes the same amount of ultrasound to emulsify the nucleus with either platform, but with the control of dual-linear phaco, emulsification can take place at lower levels of ultrasound power," Dr. Whitman said. "This minimizes the cornea's and anterior chamber's level of exposure to ultrasound."
Although mean phaco time was slightly longer using the dual-linear platform, he said he did not notice any difference in case efficiency.
"Anytime you use a little bit more finesse with a procedure-which the dual linear enables-it also means that the procedure can take a little bit more time," Dr. Whitman said.
Findings similar to other study
The findings of his study of 37 eyes are similar to the results of a large field observation study of standard and microincision cataract surgery using a wide range of phaco techniques. In this study, the dual-linear group (49 eyes) had lower mean phaco power use of 7.7%, compared with 11.6% for the single-linear group (277 eyes) and a lower mean phaco time (25.6 seconds versus 31.3 seconds). Mean EPT in the dual-linear group was 3.2 seconds versus 4.0 seconds in the single-linear group.
"The field study had a wider range of cataract densities than our small study and yet still found a lower level of phaco power and shorter EPT using the dual-linear platform," he said.
According to Dr. Whitman, the dual-linear platform has the potential to increase the speed and efficiency of the phaco procedure, and it possibly may improve its safety as well, by increasing surgeon control of both phaco and vacuum.
"The nice thing is that it can handle the whole gamut, from a rock-hard cataract to a clear lens extraction," he said. "For a clear lens extraction, you have high vacuum with this machine, and you'll find yourself working with all vacuum and no phaco power at all. And then, being a venturi machine, you have plenty of power when needed to easily break up the hard nuclei. The power is so efficient at the tip [that] you don't need a torsional handpiece.
"In addition, with this platform I have been able to convert to a 1.8-mm incision, which means shorter healing time and less astigmatism," Dr. Whitman continued.
He added that he still would like to compare corneal clarity and endothelial cell counts with both the single-linear and dual-linear platforms, and he hopes to conduct such a study within the next year.