Study of biosensing method for real-time feedback in robot-assisted vitrectomy

Samenvatting

The human vitreous humour is a viscoelastic gel in the eye which adheres strongly to the retina. Sometimes, surgical removal of the vitreous with a vitrectomy is necessary. For a vitrectomy, three instruments are placed into the eye. The vitrector cuts the vitreous and sucks it out and an infusion maintains the eye pressure by addition of balanced salt solution. A light fiber is needed for better sight, because the surgeon looks with a microscope through the pupil. The procedure can be made more efficient by automating the surgery. For this, a sensor will measure the vitreous concentration so the vitrector can move automatically to another spot when there is no vitreous left. In this report, the question of how to design a biosensor for real-time feedback in robot-assisted vitrectomy is discussed. First, the requirements are specified and after that, several potential methods for a sensor are discussed and compared. Experiments have been performed to determine the flow of the vitreous in different concentrations, showing that the flow becomes higher when the vitreous concentration drops. An experiment to determine the delay of the fluid before it reaches the sensor showed that the sensor cannot be placed at the back-end because the delay would be too high. Potential fluid analysis methods have been listed, indicating that Raman spectroscopy and absorption spectroscopy could be usable for the sensor. In this report, absorption spectroscopy in the UV-visible range was tested with vitreous concentrations between 0.1% and 100%. The data shows that absorption spectroscopy can distinguish a concentration of 1% vitreous. The next step is integrating the sensor in the vitrector. After that, the method can be tested in the actual procedure.

Datum prijs	2 dec. 2015
Originele taal	Engels
Begeleider	Menno W.J. Prins (Afstudeerdocent 1), Maarten J. Beelen (Afstudeerdocent 2) & Nicky de Jonge (Begeleider)