Purchase this article with an account.
I-Jong Wang, Lon A. Wang, Pin-Chung Lin; Intraocular Pressure Monitoring Using Moiré Patterns Generated from a Contact Lens. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):2027.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
The monitoring of intraocular pressure (IOP) variations and the measurement of IOP diurnal peaks are important for the diagnosis and the management of glaucoma disease. Continually obtaining IOP values may therefore help identify variations and spikes. In this work, a contact lens sensor with double-layer microstructures is demonstrated to produce moiré fringes for the continual characterization of IOP variations (Figure 1).
The microstructure on each layer of the contact lens was made by molding method. One rigid layer was served as reference and the other was soft to be adhered to the cornea surface so that the resultant moiré fringes could be used to detect the change of curvature caused by IOP fluctuation. The functionality of contact lens sensor was verified and the sensitivity to IOP fluctuation was characterized on a porcine eye. The variations in the moiré fringes were shown co-related with the IOP variations which were generated from standard model eyes and porcine eyes.
The radius of the porcine eye was controlled by injected water pressure. The radius variations with water pressure were measured by using a shape profiler and was around 3 µm per mmHg, which is close to variation in the human eye. For every 2 mmHg IOP increment in the porcine eye, the number of the moiré fringes in the 0 degree from the center of the pattern was varied by one (Figure 2). It was noted that the spacing of moiré fringes could be varied continuously with IOP variation, IOP variations as small as 1 mmHg could be resolved, which we believe is good enough for monitoring the IOP spikes from glaucoma disease.
The contact lens sensor was made as a fully passive and non-invasive optical device with dynamic range more than 20 mmHg and 1 mmHg resolution in IOP variation measurement. The effectiveness of the contact lens sensor was confirmed on a porcine eye experiment. Using such contact lens could provide a new and safe diagnostic method for monitoring and managing glaucoma.
This PDF is available to Subscribers Only