One and a half million times a year, the instruments of eye surgery specialist Oertli Instrumente AG are used for cataract operations. In cooperation with the Lucerne University of Applied Sciences, the Rhine Valley company is working on instruments that will make the operation safer and even more efficient.
Cataracts are an eye disease that clouds the lens of the eye. If left untreated, it can, in the worst case, lead to blindness. In medical terms, this disease is called ’cataract’. The good news is that cataracts can be operated on. Doctors perform this operation about 15 million times a year worldwide. The cloudy lens of the eye is broken up and removed, and a new artificial lens is implanted to replace it. Today, ultrasound or laser technology is available to fragment the natural lens. Both techniques are very safe and have a low complication rate. In a project supported by Innosuisse, Oertli Instrumente AG and the University of Lucerne (HSLU) have investigated how the efficiency of the operation can be increased while maintaining or even improving safety. A reduction in operating time always means less handling of the eye. This means that the risk of the operation is also reduced," explains Silvio Di Nardo, project manager at the Institute of Medical Technology at the Lucerne University of Applied Sciences. In addition, the shorter operating time reduces costs. Oertli Instrumente AG develops and produces instruments for eye surgery. It focuses on the removal of the lens using ultrasound. This method is relatively inexpensive and can be performed with a portable device. This is particularly important in developing and emerging countries.
Better surgical instruments require more basic knowledge
The first step was to find out what actually happens in the eye during an operation: Until now, the answer has been sought by building and studying experimental models. But the experts at the Institute of Medical Technology at the Lucerne University of Applied Sciences wanted to reproduce and simulate the physics of cataract surgery in numerical models first before embarking on complex experimental work. Therefore, they collaborated with specialists from the HSLU Competence Centers Autonomous Systems and Robotics and Fluid Mechanics and Numeric Methods.
Knowledge through simulation models
Researchers in the field of fluid mechanics and numerical methods specialize in creating simulation models that simulate complex flows. These models not only help in the development of hydroelectric power plants, but can also be applied to the human eye. With them, it is possible to simulate not only an existing state, but also the behavior under changed circumstances and influences - for example the size or shape of medical instruments. In this project, two methods for simulating fluidity were used and the claims of both models were always experimentally validated. The main results of this subproject are, on the one hand, safe and stable fluid simulation models and, on the other hand, optimized instrument proposals derived from these models and allowing for a more efficient removal of the lens.
The fragmentation of the lens is done with the help of ultrasound. This is where the experts from the Autonomous Systems and Robotics Competence Center were called in. They created simulation models to study the propagation of ultrasound in the eye. This information is very important for assessing the safety of this procedure: the ultrasound must break the lens, but without damaging other tissue. In another sub-project, the researchers examined, by combining simulations and experiments, how exactly the fragmentation of the lens takes place. It turned out that the fragmentation of the opaque lens occurs in a purely mechanical way, in the same way as a jackhammer. This discovery makes it possible to perform cataract surgery with even less ultrasonic energy.
Efficiency reduces risk and saves money
Thanks to the models, researchers now have a more accurate understanding of what happens in the eye during an operation. More importantly, they can calculate with the help of simulation how modified instruments or a change in instrument control will affect what happens in the eye during surgery. Based on the simulations, the head of the research project Silvio Di Nardo and his team developed proposals for solutions for more efficient and safer instruments. A team of biologists translated the results of the project into the language and way of thinking of doctors and developed a procedure for experimentally reproducing the removal of the lens. Thanks to this procedure, it is now possible to demonstrate the efficiency gains actually obtained by new instruments. Although the basis for calculation is important, it cannot replace experimental and clinical verification of the results.
Oertli Instrumente AG is currently examining several optimization proposals that have emerged from the project. The company expects to be able to bring these innovations to market within the next 24 months.