Application of graphene nanowalls in an intraocular pressure sensor

Combining crack mechanism in GNWs with the stretchability of PDMS, a contact lens sensor exhibits excellent sensitivity to intraocular pressure.

Development of a Portable Reader for an Optical Intraocular Pressure Sensor

This paper presents various designs of a handheld reader for an interferometric intraocular pressure measurement system. Reflected lights from the implanted sensor form interference fringes which can be captured using a camera. Image processing software was used to analyze the fringe pattern and determine the eye pressure. Various light sources were considered and the LED with a laser line filter was selected for its ability to generate quality fringe patterns and portability. Three generations of handheld readers have been developed and tested. Interference patterns acquired from each reader were compared to assess the limiting and promising features related to measurement time, form factor, working distance, ease of use, and quality of fringes. Results show that the DSLR-based reader has the highest quality images with the largest form factor while the smartphone-based reader offers the smallest form factor with ease of use and accessibility for the patient.

Automated, Noncontact Intraocular Pressure Home Monitoring after Implantation of a Novel Telemetric Intraocular Pressure Sensor in Patients with Glaucoma: A Feasibility Study

Purpose. Reliable and regular assessment of intraocular pressure (IOP) is important for the monitoring of patients with glaucoma. The purpose of this study was to evaluate the feasibility of a novel system for the automated, noncontact measurement of IOP. Patients and Methods. A first-generation telemetric IOP sensor was previously implanted in the ciliary sulcus of six patients with open-angle glaucoma during cataract surgery. Using this technology, automated noninvasive tonometry may be performed in a home setting. In the present study, a modified sleep mask and a modified eyepatch with incorporated coil antennae for measurements during nighttime and daytime, respectively, were tested on a single patient. Results. In this feasibility study, the 24 h wear of the prototype measuring apparatus was well tolerated. Three sequences of 24 h IOP measurements with at least 200 IOP measurements per day were performed (Sequence 1: mean 19.6 ± 2.7 mmHg, range 13.4–28.7 mmHg; Sequence 2: mean 21.0 ± 3.0 mmHg, range 13.1–30.5 mmHg; Sequence 3: mean 19.9 ± 2.4 mmHg, range 12.6–27 mmHg). Conclusions. For the first time, repeated and automated 24-hour measurements are possible using a prototype noncontact reading system after implantation of a novel telemetric IOP sensor in patients with glaucoma.