Precision in eye surgery

The surgical systems “Qube” and “Qube pro” are the technical assistants of choice for eye surgeons during cataract operations (grey star) and retina surgery. During initial start-up, BYTEC service specialists program each and every instrument together with the eye surgeons, taking their individual working methods into consideration. Additional functions, including safety functions, can be activated via eight foot pedals. This makes it easy and convenient for the surgeons to use the highly precise cutting and suction instruments that are controlled by the QUBE pro. Piezo technology allows the pressure in the system to be precisely regulated while fast-switching valves increase the cutting rates.

Lightweight, silent and precise

During cataract surgery, the opacified lens is broken up by an ultrasound probe. A high-precision suction/rinsing device, which is actuated by proportional valve MPYE from Festo, removes the lens fragments. During this procedure, the required infusion pressure is controlled by piezo
valve VEAB from Festo. After the residual tissue has been rinsed and removed, the surgeon inserts the new, artificial and clear lens. High-precision pressure regulation is also used during surgery on the anterior segment of the eye (vitrectomy).

“Safety has top priority in our development goals. When developing the components and systems, we go to the limits of what is technically feasible so that we can obtain certifications from approval organisations like the FDA,” reports Dipl.-Ing. Paul Willi Coenen, Managing Director of BYTEC. Redundant valves are therefore included for each valve function.

The technical basis for most functions is a complete pneumatic control unit consisting of solenoid valves and piezo valves. It drives the surgical tools, the vacuumassisted suction removal and the delivery of liquids. Positive characteristics of piezo valves: they are lightweight, quiet and accurate with minimal heat generation and practically wear-free.

7,500 cuts per minute

“The higher the cutting rate, the better and more precisely the surgeon can work in the anterior segment,” says Coenen, “which is why we were looking for valves which would make these high cutting rates possible.” The fast-switching valves MHA2 from Festo achieve rates of up to 7,500 cuts per minute in the QUBE pro in order to be able to use the cutter for removing tissue accurately.

Dipl.-Ing. Harald Pauls, developer of the QUBE pro eye surgery device at BYTEC: “Approaching the technical limits can only be done by searching for new solutions as collaborative partners.” This means involving specialists from a great variety of disciplines, such as physicians, physicists and chemists. “And it is important for us to have automation technology suppliers who can bring a product like the QUBE pro to series production together with us, step by step, interactively and with short reaction times,” says Pauls.

Perspective with integration technology

Together with BYTEC, Festo developed a compact valve control block for the QUBE pro. By using so-called integration technology, a manifold duct plate was created which integrates all the pneumatic connections for a protected, tubeless supply. In addition, the integration technology also allowed various hollow spaces and silencers to be included. Otherwise, this would have required separate special components. As a result, the control block requires 50% less installation space than a conventional solution with numerous individual tubing connections for each pneumatic component. The manifold duct plate has a common electrical interface for all solenoid coils and sensor signals.

A further advantage is that, thanks to pre-assembled, pretested connections, a control block can be quickly integrated into the QUBE pro surgery device. The control block is compact, easy to access and extremely quiet. “Collaboration with our project partners at Festo was a great help to us. They responded very quickly to our requirements by suggesting creative solutions and thus made a great contribution to our mutual goal,” says QUBE pro developer Pauls from BYTEC.