Intraocular Pressure Monitoring Research Articles

A Systematic Review of Teleophthalmology Services Post-COVID-19 Pandemic in New Zealand, the United Kingdom, Australia, the United States of America, and Canada.

Background: This systematic review of teleophthalmology services in Australia, the United States of America (USA), Canada, and the United Kingdom (UK) during the COVID-19 pandemic is aimed to evaluate changes in teleophthalmology, comparing them to New Zealand (NZ). Methods: A literature search of electronic databases Scopus, Proquest, PubMed, Embase, Web of Science, Cochrane Library, Google Scholar, and Google was conducted using search terms: telemedicine, ophthalmology, teleophthalmology/teleophthalmology, and COVID/COVID-19/coronavirus/covid-pandemic. Studies describing teleophthalmology services created in response to COVID-19 restrictions from March 1, 2020, to January 31, 2024, were analyzed. Results: Of the articles, 37 describing 29 discrete teleophthalmology services were included. There were 15 services in the USA, seven in the UK, two in Canada, two in Australia, and three in NZ. The models of care in the USA were well described, and teleophthalmology was used for general, external, anterior segment, neuro-ophthalmology, and oculoplastic consults, as well as for grading of fundus images in the emergency department setting. In the UK, teleophthalmology was used for general eye care, oculoplastics, and pediatric ophthalmology. In Australia, teleophthalmology was used for postglaucoma surgery monitoring of Intraocular Pressure. In NZ, teleophthalmology was used for general eye consults and triaging, but no formal models were described. Conclusion: COVID-19 offered a unique opportunity for re-examination and expansion of teleophthalmology services globally. Video-based and home-screening teleophthalmology services are feasible but have limitations. Investing in multidisciplinary and community-based technology partnerships can create more equitable teleophthalmology care models (to complement and, when necessary, replace traditional in-person consults), within existing frameworks, making eye care more accessible and efficient.

Liquid-alloy-based dual sensing elements contact lens sensor for continuous intraocular pressure monitoring

Intraocular pressure (IOP) fluctuation is an independent risk factor for glaucoma and a key to clarify its pathogenesis. We have developed a contact lens integrated with a conformal LC resonance circuit made of liquid alloy (Galinstan) for non-invasive continuous IOP monitoring. The contact lens is fabricated using polydimethylsiloxane (PDMS), in which the LC resonance circuit can sense corneal strain proportionally caused by IOP variation. The Galinstan configuration is formed to the designed pattern by UV-laser treating the carbon-doped Ecoflex (c-Ecoflex) stamps and then selectively transferring the Galinstan onto the stamp to form the LC resonance circuit pattern. The tests conducted on silicone model eyes demonstrate high sensitivity in the frequency responses to variations in IOP, reaching 649 ppm/mmHg. IOP measurement on human eyes during head-down tilt bedrest confirms its applicability. With process optimization, this contact lens sensor has great potential for mass production and wide application in monitoring IOP.

Neuroprosthetic contact lens enabled sensorimotor system for point-of-care monitoring and feedback of intraocular pressure

The wearable contact lens that continuously monitors intraocular pressure (IOP) facilitates prompt and early-state medical treatments of oculopathies such as glaucoma, postoperative myopia, etc. However, either taking drugs for pre-treatment or delaying the treatment process in the absence of a neural feedback component cannot realize accurate diagnosis or effective treatment. Herein, a neuroprosthetic contact lens enabled sensorimotor system is reported, which consists of a smart contact lens with Ti3C2Tx Wheatstone bridge structured IOP strain sensor, a Ti3C2Tx temperature sensor and an IOP point-of-care monitoring/display system. The point-of-care IOP monitoring and warning can be realized due to the high sensitivity of 12.52 mV mmHg−1 of the neuroprosthetic contact lens. In vivo experiments on rabbit eyes demonstrate the excellent wearability and biocompatibility of the neuroprosthetic contact lens. Further experiments on a living rate in vitro successfully mimic the biological sensorimotor loop. The leg twitching (larger or smaller angles) of the living rat was demonstrated under the command of motor cortex controlled by somatosensory cortex when the IOP is away from the normal range (higher or lower).

Ocular Perfusion Pressure in Primary Open Angle

Purpose: To determine thecorrelation of Mean Ocular Perfusion Pressure (MOPP) with Mean Arterial Pressure (MAP) in primary open angle glaucoma (POAG)and normal tension glaucoma. Study Design: Cross sectional study. Place and Duration of Study: Khyber Teaching hospital, Peshawar from July, 2017 to December, 2019. Methods: A total of 375 patients with POAG were admitted in the hospital. Patients with variable blood pressure (BP) on admission or history of blood pressure or using anti-hypertensive drugs were selected. Patients with secondary Glaucoma, Primary Angle closure Glaucoma, patients with Diabetes mellitus and age below 40 years were excluded. Finally,200 patients were recruited by convenience sampling. Forty-eight hours monitoring of MAP and Intra ocular pressure (IOP) phasing were done. MAP, MOPP and peak IOP were charted. Results: MAP and MOPP variabilitywas observed in 53% of patients with POAG. The Pearson co-relation coefficient for those patients in which intervention had yet not been done was -0.460 suggesting a moderate negative correlation between MOPP and IOP (p value <0.01). In IOP controlled patients, the coefficient was -0.346 (p<0.01). Theresults showed a negative correlation between the two values in both data sets. The correlation co-efficient for MAP and IOP in both pre-admission and controlled IOP patients showed strong positive correlation (0.816 and 0.854 respectively for two tailed tests with 0.01 significance). Conclusion: MOPP, MAP and IOP are correlated and their determination is important in all Primary Open Angle Glaucoma particularly in Normal Tension Glaucoma.

Assessing the value of the water drinking test in glaucoma-a systematic review and meta-analysis.

This systematic review and meta-analysis examines the relationship between intraocular pressure (IOP) parameters derived from the water drinking test (WDT) and diurnal IOP monitoring, and evaluates the reproducibility of the WDT and its association with future glaucomatous visual field (VF) loss. A literature search was performed on PubMed, EMBASE, and Cochrane Library from inception to 31 March 2023. Cohort, cross-sectional and observational studies reporting WDT results in glaucoma patients were included. Meta analysis with random-effect model was performed using "metafor" package in R version 3.2.1. 641 studies were identified on initial literature search. 38 studies (2479 subjects) were included in final analysis. Meta-analytic estimates of 5 studies (310 subjects) found strong positive correlation in peak IOP between the WDT and diurnal IOP monitoring (r = 0.92, 95% CI = 0.75, 1.08, p < 0.0001). However, there was only weak positive correlation for IOP fluctuation between both methods (r = 0.26, 95% CI = 0.06,0.47, p < 0.0001). Meta-analytic estimates of 3 studies (189 subjects) suggested a trend of the diurnal peak IOP being lower than that derived from the WDT (MD = -2.37 mmHg, 95% Limit of Agreement (LOA) =-5.58,0.84, p = 0.147). Two studies found that a higher WDT peak IOP was associated with greater future VF progression. Two studies demonstrated good reproducibility in peak IOP measurements for WDTs conducted across different days. In conclusion, there was a strong positive correlation between IOP peak measurements from the WDT and diurnal IOP monitoring in glaucoma patients. The WDT peak IOP demonstrated good reproducibility and may be associated with greater future VF progression.

24-hour intraocular pressure monitoring: past, present, and future

24-hour intraocular pressure monitoring: past, present, and future

Temperature Self-Compensating Intelligent Wireless Measuring Contact Lens for Quantitative Intraocular Pressure Monitoring.

Flexible bioelectronic devices that can perform real-time and accurate intraocular pressure (IOP) monitoring in both clinical and home settings hold significant implications for the diagnosis and treatment of glaucoma, yet they face challenges due to the open physiological environment of the ocular. Herein, we develop an intelligent wireless measuring contact lens (WMCL) incorporating a dual inductor-capacitor-resistor (LCR) resonant system to achieve temperature self-compensation for quantitative IOP monitoring in different application environments. The WMCL utilizes a compact circuitry design, which enables the integration of low-frequency and high-frequency resonators within a single layer of a sensing circuit without causing visual impairment. Mechanically guided microscale 3D encapsulation strategy combined with flexible circuit printing techniques achieves the surface-adaptive fabrication of the WMCL. The specific design of frequency separation imparts distinct temperature response characteristics to the dual resonators, and the linear combination of the dual resonators can eliminate the impact of temperature variations on measurement accuracy. The WMCL demonstrates outstanding sensitivity and linearity in monitoring the IOP of porcine eyes in vitro while maintaining satisfactory measurement accuracy even with internal temperature variations exceeding 10 °C. Overcoming the impact of temperature variations on IOP monitoring from the system level, the WMCL showcases immense potential as the next generation of all-weather IOP monitoring devices.

Neuroprotective effects of acteoside in a glaucoma mouse model by targeting Serta domain-containing protein 4.

To explore the therapeutic effect and main molecular mechanisms of acteoside in a glaucoma model in DBA/2J mice. Proteomics was used to compare the differentially expressed proteins of C57 and DBA/2J mice. After acteoside administration in DBA/2J mice, anterior segment observation, intraocular pressure (IOP) monitoring, electrophysiology examination, and hematoxylin and eosin staining were used to analyze any potential effects. Immunohistochemistry (IHC) assays were used to verify the proteomics results. Furthermore, retinal ganglion cell 5 (RGC5) cell proliferation was assessed with cell counting kit-8 (CCK-8) assays. Serta domain-containing protein 4 (Sertad4) mRNA and protein expression levels were measured by qRT-PCR and Western blot analysis, respectively. Proteomics analysis suggested that Sertad4 was the most significantly differentially expressed protein. Compared with the saline group, the acteoside treatment group showed decreased IOP, improved N1-P1 wave amplitudes, thicker retina, and larger numbers of cells in the ganglion cell layer (GCL). The IHC results showed that Sertad4 expression levels in DBA/2J mice treated with acteoside were significantly lower than in the saline group. Acteoside treatment could improve RGC5 cell survival and reduce the Sertad4 mRNA and protein expression levels after glutamate injury. Sertad4 is differentially expressed in DBA/2J mice. Acteoside can protect RGCs from damage, possibly through the downregulation of Sertad4, and has a potential use in glaucoma treatment.

Intraocular Pressure Monitoring Smart Contact Lens with High Environmental Stability

AbstractSmart contact lenses (SCLs), integrating various functional components, serve as a platform for wirelessly intraocular pressure (IOP) monitoring. Accurate and dynamic measurements offer crucial clinical references for patients with ocular hypertension. Nevertheless, the complex ocular environment poses great challenges, particularly for inductor–capacitor–resistor (LCR) type IOP sensors, which suffer signal instability due to variations of ocular dielectric properties. Here, an innovative IOP monitoring sensor with robust environmental stability, achieved by integrating the ground shield, is proposed. Employing a capacitive pressure sensor with porous polydimethylsiloxane (PDMS) structure encased in a hydrogel, the study successfully demonstrates high‐sensitivity monitoring of IOP changes using in vitro porcine eyes. This optimized design empowers the wireless IOP sensor with a sensitivity of 1.15 ‰/mmHg. It exhibits exceptional frequency stability after undergoing 100 wear cycles on ten distinct porcine eyes and remains reliable across a wide range of metabolite concentrations typical of normal eyes. Notably, any observed frequency shift translates into IOP changes within a 3 mmHg range, showcasing its suitability for repeated use and daily IOP monitoring.

Non-invasive FBG-based contact lens for continuous intraocular pressure monitoring

The intraocular pressure (IOP), or pressure inside the eye, is one of the key indicator for glaucoma diagnosis and treatment. The present work shows the design and fabrication of a non-invasive Fiber Bragg Grating (FBG) based contact lens for continuous IOP monitoring. By employing wet etching to reduce the FBG diameter, FBG based contact lens sensitivity and mechanical flexibility are enhanced. The contact lens is made of an optical fiber with a small core diameter that has an inscribed FBG of length 3 mm and is etched for a length of 40 mm to facilitate coiling the eFBG during fabrication. The soft contact lens was fabricated using flexible thin film technology with a transparent and flexible etched Fiber Bragg Grating (eFBG) integrated within flexible polydimethylsiloxane (PDMS) for sensing corneal deformations brought about by IOP variations. Experimental studies on the bionic eyeball model show that the Bragg wavelength shift is highly linear (r2 = 0.9694), with a very good sensitivity of 49.243 pm/mmHg in the IOP pressure range of 0 to 50 mmHg. Due to its ease of fabricating, simplicity of design, and ability to continuously measure pressure with good repeatability and stability, the proposed sensor thus offers a potential solution for IOP monitoring.

Remote and low-cost intraocular pressure monitoring by deep learning of speckle patterns.

Glaucoma, a leading cause of global blindness, disproportionately affects low-income regions due to expensive diagnostic methods. Affordable intraocular pressure (IOP) measurement is crucial for early detection, especially in low- and middle-income countries. We developed a remote photonic IOP biomonitoring method by deep learning of the speckle patterns reflected from an eye sclera stimulated by a sound source. We aimed to achieve precise IOP measurements. IOP was artificially raised in 24 pig eyeballs, considered similar to human eyes, to apply our biomonitoring method. By deep learning of the speckle pattern videos, we analyzed the data for accurate IOP determination. Our method demonstrated the possibility of high-precision IOP measurements. Deep learning effectively analyzed the speckle patterns, enabling accurate IOP determination, with the potential for global use. The novel, affordable, and accurate remote photonic IOP biomonitoring method for glaucoma diagnosis, tested on pig eyes, shows promising results. Leveraging deep learning and speckle pattern analysis, together with the development of a prototype for human eyes testing, could enhance diagnosis and management, particularly in resource-constrained settings worldwide.

An Ultrasensitive Ti3C2Tx MXene-based Soft Contact Lens for Continuous and Nondestructive Intraocular Pressure Monitoring.

Wearable soft contact lens sensors for continuous and nondestructive intraocular pressure (IOP) monitoring are highly desired as glaucoma and postoperative myopia patients grow, especially as the eyestrain crowd increases. Herein, a smart closed-loop system is presented that combines a Ti3C2Tx MXene-based soft contact lens (MX-CLS) sensor, wireless data transmission units, display, and warning components to realize continuous and nondestructive IOP monitoring/real-time display. The fabricated MX-CLS device exhibits an extremely high sensitivity of 7.483mV mmHg-1, good linearity on silicone eyeballs, excellent stability under long-term pressure-release measurement, sufficient transparency with 67.8% transmittance under visible illumination, and superior biocompatibility with no discomfort when putting the MX-CLS sensor onto the Rabbit eyes. After integrating with the wireless module, users can realize real-time monitoring and warning of IOP via smartphones, the demonstrated MX-CLS device together with the IOP monitoring/display system opens up promising platforms for Ti3C2Tx materials as the base for multifunctional contact lens-based sensors and continuous and nondestructive IOP measurement system.

Continuous 24-hour intraocular pressure monitoring in normal Chinese adults using a novel contact lens sensor system

AimsTo investigate the physiological nyctohemeral intraocular pressure (IOP) rhythms of normal Chinese adults using a novel contact lens sensor system (CLS) that can output IOP in millimetres of mercury (mm...

An Uneventful Case of Unresolved Suprachoroidal Hemorrhage After Cataract Surgery: When to Operate?

Introduction : Suprachoroidal hemorrhage (SCH) is a rare, but potentially vision-threatening condition. The management options for SCH varied and still debatable.&#x0D; Case Illustration : Female 54 years old with chief complaint blurry vision of right eye (RE) since four days after she underwent cataract surgery. She also experienced radiating pain from RE with nausea and vomiting. No history of elevated intraocular pressure (IOP) before the surgery. Her left eye was blind for 20 years prior due to an unknown cause. Visual acuity (VA) on presentation was light perception good projection and IOP was 34mmHg. There was 2.5mm hyphema and fibrin on the anterior chamber. Lens appeared to be aphakic and there was lens material at pupillary margin. Ultrasonography (USG) of RE showed choroidal elevation with medium to high spike and positive after movement indicating SCH. She was hospitalised for IOP monitoring and serial USG was performed to monitor the hemorrhage. Six days after admission, IOP remain elevated despite medications and SCH didn’t resolve, then vitrectomy and scleral drainage was performed. Postoperative exam showed improved VA to 0.5/60, IOP to 16mmHg without medication, and reduced suprachoroidal hemorrhage on USG.&#x0D; Discussion : It’s imperative to perform complete evaluation of ocular and systemic conditions in preoperative period to prevent SCH. Ultrasonography is crucial during the close follow-up after developing SCH, it also aids in the timing of surgical intervention.&#x0D; Conclusion : Vitrectomy with scleral drainage is a valuable approach in managing extensive SCH, a condition generally associated with poor prognosis.

Causes and management strategies for elevated intraocular pressure after implantable collamer lens implantation.

With the widespread application of Implantable Collamer Lens (ICL) implantation surgery in the field of myopia correction, a comprehensive understanding of its potential complications, especially those related to intraocular pressure (IOP), becomes crucial. This article systematically reviews various complications that may lead to IOP elevation after ICL surgery. Firstly, common complications after ICL surgery, including residual viscoelastic, steroid response, and excessive vault of the ICL, are detailed, emphasizing their potential impact on intraocular pressure. Regarding residual viscoelastic, we delve into its direct relationship with postoperative elevated IOP and possible preventive measures. For steroid response, we stress the importance of timely adjustment of steroid therapy and monitoring intraocular pressure. Additionally, excessive vault of the ICL is considered a significant potential issue, and we elaborate on its mechanism and possible management methods. In further discussion, we focus on relatively rare complications such as Toxic Anterior Segment Syndrome (TASS), Urrets-Zavalia Syndrome (UZS), Pigment Dispersion Syndrome (PDS), and malignant glaucoma. For these relatively rare complications, this review thoroughly explores their potential mechanisms, emphasizes the importance of prevention, and provides guidance for early diagnosis and treatment. This is a comprehensible review that aims to offer eye care professionals a comprehensive understanding and effective management guidance for complications of elevated IOP after ICL surgery, ultimately providing optimal care for patients' visual health.

Displacement-pressure biparametrically regulated softness sensory system for intraocular pressure monitoring.

High intraocular pressure (IOP) is one of the high-risk pathogenic factors of glaucoma. Existing methods of IOP measurement are based on the direct interaction with the cornea. Commercial ophthalmic tonometers based on snapshot measurements are expensive, bulky, and their operation requires trained personnel. Theranostic contact lenses are easy to use, but they may block vision and cause infection. Here, we report a sensory system for IOP assessment that uses a soft indentor with two asymmetrically deployed iontronic flexible pressure sensors to interact with the eyelid-eyeball in an eye-closed situation. Inspired by human fingertip assessment of softness, the sensory system extracts displacement-pressure information for soft evaluation, achieving high accuracy IOP monitoring (>96%). We further design and custom-make a portable and wearable ophthalmic tonometer based on the sensory system and demonstrate its high efficacy in IOP screening. This sensory system paves a way towards cost-effective, robust, and reliable IOP monitoring.

Impact of atropine use for myopia control on intraocular pressure in children: A comprehensive review including postpupil dilation intraocular pressure changes.

Topical atropine has been widely used for controlling myopia progression in children, yet its long-term efficacy and safety, including potential intraocular pressure (IOP) elevation, are still being studied. The mydriasis and cyclopegia induced by atropine may reduce traction on the trabecular meshwork, together with pigment released into anterior chamber due to the friction between the iris and lens during pupil dilation, may obstruct and reduce the trabecular outflow. This review first explores postdilation IOP changes across different groups - healthy individuals, glaucoma patients, and children. The response to pupil dilation varies widely, with IOP potentially increasing or decreasing. Glaucoma patients, whether with open or closed-angle glaucoma, may experience more significant IOP rises postdilation. The second section examines IOP effects in children using topical atropine for myopia, where most of the 25 reviewed studies showed nonsignificant IOP changes, although slight increases were observed in a few. In addition, no alterations in the retinal nerve fiber layer thickness were found. However, the research on children's IOP under topical atropine is constrained by small sample sizes, cross-sectional studies, brief follow-ups, and often lacks control groups or pretreatment IOP measurements. Given the extended atropine use for myopia and the significant individual variation in IOP response, we recommend routine IOP monitoring for children receiving topical atropine.

Advances and Challenges in Wearable Glaucoma Diagnostics and Therapeutics.

Glaucoma is a leading cause of irreversible blindness, and early detection and treatment are crucial for preventing vision loss. This review aims to provide an overview of current diagnostic and treatment standards, recent medical and technological advances, and current challenges and future outlook for wearable glaucoma diagnostics and therapeutics. Conventional diagnostic techniques, including the rebound tonometer and Goldmann Applanation Tonometer, provide reliable intraocular pressure (IOP) measurement data at single-interval visits. The Sensimed Triggerfish and other emerging contact lenses provide continuous IOP tracking, which can improve diagnostic IOP monitoring for glaucoma. Conventional therapeutic techniques include eye drops and laser therapies, while emerging drug-eluting contact lenses can solve patient noncompliance with eye medications. Theranostic platforms combine diagnostic and therapeutic capabilities into a single device. Advantages of these platforms include real-time monitoring and personalized medication dosing. While there are many challenges to the development of wearable glaucoma diagnostics and therapeutics, wearable technologies hold great potential for enhancing glaucoma management by providing continuous monitoring, improving medication adherence, and reducing the disease burden on patients and healthcare systems. Further research and development of these technologies will be essential to optimizing patient outcomes.

PAUL device implantation in paediatric glaucoma patients with LTBP2 mutation: Case reports

Purpose: Latent‐transforming growth factor beta‐binding protein 2 (LTBP2) is a fibrillin‐related extracellular matrix protein. The protein is expressed in the ciliary body, and mutations in its gene lead to primary paediatric glaucoma due to anterior segment dysgenesis. These mutations in the Greek area appear almost exclusively in Roma families. In this work, we present the surgical treatment of two patients with PAUL® device implantation, and their preoperative and postoperative course.Methods: Case Reports.Results: Case 1: A 2‐month‐old female patient, the fifth child of a Roma family with an older sister with paediatric glaucoma, presented to the Ophthalmology clinic of our hospital with microspherophakia and megalocornea, a phenotype compatible with a mutation of the LTBP2 gene. She underwent a phakectomy for lens dislocation in both eyes. At the age of 2.5 years, she was diagnosed with hypertony and started topical treatment. After two years of treatment escalation and unsuccessful management of intraocular pressure, at the age of 4.5 years it was decided to implant a PAUL® glaucoma implant in her left eye. Case 2: An 8‐month‐old male patient, child of a Roma family, similarly presented with microspherophakia and megalocornea as well as hypertony. In addition to topical treatment, he underwent peripheral iridectomies and phakectomies in both eyes. After years of treatment escalation and unsuccessful management of intraocular pressure, at the age of 6.5 years it was decided to implant a PAUL® glaucoma implant in his left eye. We describe the surgical procedures as well as their postoperative course.Conclusions: Regular monitoring of intraocular pressure is recommended in children with megalocornea, microspherophakia and/or ectopia lentis. Genetic testing of the LTBP2 gene is recommended in these patients. It is important to raise awareness in the ophthalmological community regarding the recognition of this phenotype in children of Roma families. The PAUL® device is one of the options for treating drug‐resistant paediatric glaucoma.

Main issues in penetrating keratoplasty.

This review explores contemporary challenges in penetrating keratoplasty (PK), focusing on technical intricacies, technological advancements, and strategies for preventing graft rejection. A systematic literature search from January 2018 to July 2023 was conducted across PubMed, Cochrane, Web of Science, Scopus, and EMBASE. The inclusion criteria comprised studies on PK and its comparison with other corneal pathologies, with emphasis on keratoconus (KC). Two independent reviewers screened studies, extracting relevant data. The review covers PK evolution, highlighting infra-red femtosecond lasers' impact on graft shapes, minimizing astigmatism, and enhancing wound healing. Graft rejection, a primary complication, is examined, detailing risk factors and preventive measures. Preoperative considerations, diagnostic techniques for rejection, and PK in KC are discussed. Postoperative care's significance, including intraocular pressure monitoring and steroid administration, is emphasized. The paper concludes with a comprehensive approach to prevent graft rejection, involving topical and systemic medications. An outlook on evolving monoclonal antibody research is presented. As the field progresses, personalized approaches and ongoing therapeutic exploration are expected to refine strategies, enhancing PK outcomes.