Phase Focus Ltd reports on how the Brien Holden Vision Institute is applying the Phasefocus high-precision Lens Profiler to assist in the development of new contact lenses. The Brien Holden Vision Institute is located at the University of New South Wales in Syndney, Australia.
The core business of the Brien Holden Vision Institute is to create new ways to improve vision outcomes for people whose sight is affected by refractive error. Collectively, the conditions of myopia, presbyopia, hyperopia and astigmatism (all regarded as ‘refractive errors’) impair the vision of billions of people worldwide. An area of particular interest for the Brien Holden Vision Institute is the use of novel optics with the potential to provide advanced modes of vision correction using contact lenses. The Phasefocus Lens Profiler is capable of accurately measuring power profiles of soft contact lenses. Those measurements are helping scientists to understand and improve the distribution of optical power over the lens surface.
Project Manager, Dr. Fabian Conrad, and Director of Technology, Dr. Klaus Ehrmann, of the Vision Cooperative Research Centre, in which the Institute is a participant, are interested in accurately characterising the thickness and power profiles of soft contact lenses. These measurements aid in the Quality Control (QC) process as well as general R&D of novel contact lens designs. The Institute says that the use of ptychography, the scientific name for the Phasefocus Virtual Lens technology, is the most accurate technique for the measurement of contact lens thickness. Describing his experiences, Dr. Ehrmann said “We have tried to use confocal microscopy to measure thickness and edge profiles of soft lenses, but that wasn't very successful. That's when we developed our own tactile thickness profilers. However, we now see the Phasefocus system having strong advantages over other contact lens metrology systems for the measurement of lens thickness. It is unparalleled in terms of accuracy and resolution.”
The Phasefocus Lens Profiler has been adopted by major lens manufacturers and research institutes as the de facto reference method for determination of soft lens thickness. As well as providing lens manufacturers with valuable insight for lens design and manufacture, the high precision thickness maps generated by the Lens Profiler can enable eye care practitioners to better understand the clinical applications of complex lenses. With the growing interest in specialist soft lenses the potential for wider use of this technology is considerable.