New sensor provides simpler measurement of eye pressure

On Friday, May 31, Anders Eklund, Department of Radiation Sciences, Medical Technology, Umeå University, Sweden, will defend his dissertation evaluating a new and simpler instrument for measuring the pressure of eye fluids, a key risk factor in glaucoma. Anders Eklund has a master’s in engineering and works at the Unit for Medical Technology and Informatics, Northern Sweden University Hospital. He has further developed and assessed a new type of sensor based on vibration technology. His work has targeted medical applications, above all measuring pressure in the eye and hardness in bodily tissue. High pressure in eye fluid is one of the prime risk factors in glaucoma. Intraocular pressure is routinely metered at eye clinics. The pressure is determined by flattening the cornea to make both the surface of the contact and the force of the contact measurable.

The dissertation presents a new and simpler method for measuring intraocular pressure: a system of sensors based on a piezo-electrically vibrating sensor element registers changes in the frequency of resonance, which is related to the contact surface. This resonance sensor is mounted on a force sensor, and when the instrument has been placed against the cornea, both the force and the surface of the contact are measured quickly and simultaneously; the eye pressure is determined on the basis of a coefficient between them. The results show that a simpler and quicker method of measuring pressure is possible thanks to this technique.
The capacity of this vibration sensor technique to measure contact surfaces has also been utilized in judging the hardness of prostate tissue removed by surgery. The study shows that the sensor can capture differences in hardness owing to the varying composition of different tissues. The composition and consistency of bodily tissues often change under disease conditions, such as cancer, and ultimately it should be possible to employ sensor technique to get an objective reading of tissue hardness, thereby improving diagnoses.