Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
Mächler, M.
Are the results of the Contact Lens Sensor Triggerfish® influenced by light?
Humanmedizin; [ Diplomarbeit ] Graz Medical University; 2016. pp. 92
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- Autor*innen der Med Uni Graz:
- Betreuer*innen:
- Faschinger Christoph
- Altmetrics:
- Abstract:
- Introduction: Glaucoma is one of the most common diseases in ophthalmology with intraocular pressure (IOP) as its most important treatable risk factor. Over eight million people per year are losing their eyesight due to this condition. Despite this over 50% of glaucoma patients are still undiagnosed. The company Sensimed announced a new method in 2009 to record and estimate fluctuations in IOP over a 24-hour period. By placing a Contact Lens Sensor (CLS) onto the eye, changes in intraocular volume can be measured pseudo-continuously. However, validity has yet to be evaluated. Some studies showed that the new device may be prone to noise and artifacts in its profile and that it shows certain ‘fluctuations’, which cannot be explained. We therefore sought to examine the influence of light on the CLS. Furthermore we analyzed current literature regarding the usability of the new device. Material and methods: The CLS called Triggerfish features a soft contact lens with implemented strain gauges to measure changes in corneal curvature, which were found to correlate with IOP. We developed a study design in which the CLS was shined on by different kind of light sources with different brightnesses during its measurement. Illuminance and temperature were recorded throughout the process and the 24-hour TF profiles were analyzed. Results: We did eight test runs, each with different sources of light, brightnesses and intervals. In seven out of eight tests the night periods, during which close to complete darkness was recorded, showed a rather quiet profile. In contrast, profiles recorded during the daytime, when ambient light was present, showed various spikes and fluctuations. However, it was not possible to find a certain correlation between illuminance and disturbances in the 24-hour profile. We found that temperature has an ambiguous influence on the profile, which has already been stated in recent literature. Conclusion: The CLS is not influenced by light intensity per se, although there are findings supporting the assumption that light might be a factor in creating noise to some degree. Temperature is influencing the profile to a certain point and might be responsible for some of the known artifacts.