Can a contact lens sensor predict the success of trabectome surgery?

A first-in-human pilot study of a novel electrically-passive metamaterial-inspired resonator-based ocular sensor embedded contact lens monitoring intraocular pressure fluctuations

Glaucoma is a leading cause of blindness with no cure, but early treatment and effective monitoring can often slow the progression of the disease. Monitoring of glaucoma is based on the measurement of intra-ocular pressure (IOP) that is a physiological parameter related to the mechanical state and parameters of the eye. Conventionally, diagnosing and assessing the progression of glaucoma is based on the method of measuring IOP discretely at clinics. Recent studies have demonstrated the importance of continuously monitoring IOP for 24 h to elucidate the effect of circadian rhythm. In this work, a metamaterial-inspired electrically-passive sensor-embedded contact lens is presented to monitor the IOP fluctuations based on a first-in-human pilot study. The sensor inside the contact lens is an electrically passive, metamaterial-based resonator that can be measured using a wearable antenna patch. The system has been tested with six healthy volunteers during an experiment to induce deliberate IOP changes via water-loading and placing the individuals in supine position using a recliner seat. The initial data compared with tonometer measurements suggest that the system can be used to assess the variation of IOP continuously.

Advancements in Wearable and Implantable Intraocular Pressure Biosensors for Ophthalmology: A Comprehensive Review

Glaucoma, marked by its intricate association with intraocular pressure (IOP), stands as a predominant cause of non-reversible vision loss. In this review, the physiological relevance of IOP is detailed, alongside its potential pathological consequences. The review further delves into innovative engineering solutions for IOP monitoring, highlighting the latest advancements in wearable and implantable sensors and their potential in enhancing glaucoma management. These technological innovations are interwoven with clinical practice, underscoring their real-world applications, patient-centered strategies, and the prospects for future development in IOP control. By synthesizing theoretical concepts, technological innovations, and practical clinical insights, this review contributes a cohesive and comprehensive perspective on the IOP biosensor's role in glaucoma, serving as a reference for ophthalmological researchers, clinicians, and professionals.

Twenty Four Hour Intraocular Pressure Indicators Distinguish Normal Tension Glaucoma from Healthy Eyes Measured with a Contact Lens Sensor

PRCIS

The cut-off values of CLS.

PURPOSE

We conducted the present study to determine (1) the best factor for distinguishing normal tension glaucoma (NTG) and non-glaucoma subjects based on the intraocular pressure (IOP) values measured by a contact lens sensor (CLS) and (2) the optimal cut-off values of that factor.

SUBJECTS AND METHODS

The eyes of 18 non-glaucoma subjects and 26 NTG patients were examined. We evaluated five indicators: maximum IOP value, standard deviation (SD), IOP fluctuation range, the cosine-fit curve amplitude, and the amplitude of dual-harmonic regression values. We determined the indicators' cut-off values to distinguish between non-glaucoma subjects and NTG patients with the area under the curve (AUC).

RESULTS

The mean IOP values were 12.3±2.7 mmHg in the non-glaucoma eyes and 12.5±3.1 mmHg in the NTG eyes (P=0.824). All five indicators were significantly higher in the NTG group. The best factor to distinguish the non-glaucoma subjects and NTG patients was the IOP fluctuation range (P<0.0001, AUC=0.844); the cut-off level value was 436.5 millivolt equivalents.

CONCLUSIONS

24 hour IOP measurements with a CLS showed that among IOP indicators studied, the range of IOP fluctuation was most important and significantly larger in NTG eyes compared to non-glaucoma eyes.

Outcome, influence factor and development of CLS measurement in continuous IOP monitoring: A narrative review

A large fluctuation in intraocular pressure (IOP) and a high peak IOP remain the risk factors for progressive visual field loss in patients with glaucoma, which is a leading cause of irreversible blindness. However, IOP measurements during working time cannot provide sufficient information on IOP to guide clinicians in setting IOP target values. Contact lenses are extensively used in ophthalmology to correct the refractive error, and recently, they are serving as platforms for detection and drug delivery. Contact lens sensor (CLS) is a feasible and promising approach to continuously monitor IOP, with superior tolerance, non-invasiveness, and without sleep disturbance. The present work reviewed the associations between progressive course and Triggerfish® CLS outputs as well as the relationship between treatments and Triggerfish® CLS outputs. Moreover, it further summarized state-of-the-art CLS devices of the past decade.