Icare Home Tonometer: A Review of Characteristics and Clinical Utility

The relationship between intraocular pressure and glaucoma: An evolving concept

Intraocular pressure (IOP) is the most important modifiable risk factor for glaucoma and fluctuates considerably within patients over short and long time periods. Our field's understanding of IOP has evolved considerably in recent years, driven by tonometric technologies with increasing accuracy, reproducibility, and temporal resolution that have refined our knowledge regarding the relationship between IOP and glaucoma risk and pathogenesis. The goal of this article is to review the published literature pertinent to the following points: 1) the factors that determine IOP in physiologic and pathologic states; 2) technologies for measuring IOP; 3) scientific and clinical rationale for measuring diverse IOP metrics in patients with glaucoma; 4) the impact and shortcomings of current standard-of-care IOP monitoring approaches; 5) recommendations for approaches to IOP monitoring that could improve patient outcomes; and 6) research questions that must be answered to improve our understanding of how IOP contributes to disease progression. Retrospective and prospective data, including that from landmark clinical trials, document greater IOP fluctuations in glaucomatous than healthy eyes, tendencies for maximal daily IOP to occur outside of office hours, and, in addition to mean and maximal IOP, an association between IOP fluctuation and glaucoma progression that is independent of mean in-office IOP. Ambulatory IOP monitoring, measuring IOP outside of office hours and at different times of day and night, provides clinicians with discrete data that could improve patient outcomes. Eye care clinicians treating glaucoma based on isolated in-office IOP measurements may make treatment decisions without fully capturing the entire IOP profile of an individual. Data linking home blood pressure monitors and home glucose sensors to dramatically improved outcomes for patients with systemic hypertension and diabetes and will be reviewed as they pertain to the question of whether ambulatory tonometry is positioned to do the same for glaucoma management. Prospective randomized controlled studies are warranted to determine whether remote tonometry-based glaucoma management might reduce vision loss and improve patient outcomes.

Comparison of intracompartment pressure changes in tibial plateau fractures and controlled people: A pilot study

OBJECTIVE

Acute compartment syndrome (ACS) is a serious medical condition that can be encountered in tibial plateau fractures. However, no studies of compartment pressure changes in patients with tibial plateau fractures compared to patient without fractures have been reported. To obtain a comprehensive understanding of the pressure changes in patients with fractures, we monitored and recorded the compartment pressure and attempted to reveal the potential pressure release function of the human fascia.

MATERIALS AND METHODS

Cohorts of 43 normal individuals and 23 patients (initial 33, 10 were excluded due to inclusion criteria) and include the number of patients who completed the study with closed tibial fractures (the fracture group, FG, which comprised 6 men and 17 women) were included in this retrospective research. Compartment pressures were measured with Icare, a device that is traditionally used to measure intraocular pressure. Results of measurements at 6 different locations in the lower limb were recorded and compared for three days (days 2, 3, and 4 post fracture) between normal cohort (CG) and fracture cohort (FG) patients.

RESULTS

The compartment pressures were comparable at each pressure measurement site (upper, middle and lower) in patients of the CG and the FG. Compared with the CG patients, there was a significant increase in compartment pressure at the upper lateral location in 18-45-year-old patients in the FG (P = 0.013) and at the upper lateral (P = 0.004) and medial locations (P = 0.005) in 46-69-year-old patients, and the values tended to normalize over time. Compared with the contralateral normal limb of patients in the FG, there was a significant increase in compartment pressure at the upper lateral location in 18-45-year-old patients (P = 0.009) and at the upper lateral (P = 0.015) and medial locations (P = 0.016) in 46-69-year-old patients on the fractured side. Based on different fracture classifications, there were no significant differences in compartment pressure at the medial (upper, middle and lower) locations when compared with pressures at the corresponding lateral sites of measurement.

CONCLUSION

The results of this study revealed that the fascial compartment as a whole can release the increased intracompartment pressure after fracture to prevent complications such as acute compartment syndrome caused by a continued increase in pressure. The Icare as a portable device, is potentially useful in compartmental pressure measurement especially in emergency room.

Test-Retest Reliability of Intraocular Pressure Measurements With Office-Based Versus Home-Based Rebound Tonometers

PRCIS

Intraocular pressure (IOP) measurements obtained with the HOME2 rebound tonometer are interchangeable with measurements obtained using the office-based IC100 and IC200 rebound tonometers, making characterization of circadian IOP achievable with no inter-device sources of variability.

OBJECTIVE

To evaluate test-retest reliability between IOP measurements obtained with a home rebound tonometer operated by patients and those obtained with office rebound tonometers operated by experienced clinical staff.

METHODS

After training and practice with a home rebound tonometer (iCare HOME2) in a randomly selected eye, patients with established or suspected open angle glaucoma underwent IOP measurement in the fellow eye as follows in randomized order: 3 good quality measurements with the iCare IC100 operated by experienced clinical staff, 3 good quality measurements with the iCare IC200 operated by experienced clinical staff, and 3 good quality measurements with the HOME2 operated by the patient. The Shrout-Fleisch intraclass correlation coefficient (ICC; 2,1) was the measure of reliability utilized based on the model using 2-way random effects, absolute agreement, and single measurement.

RESULTS

Thirty eyes of 30 patients were evaluated. The Pearson correlation coefficient ( r ) for IOP measurements taken with the IC100 and HOME2 was 0.97, with the IC200 and HOME2 was 0.96, and with the IC100 and IC200 was 0.97. Test-retest reliability between HOME2 and IC100 (ICC: 0.90), HOME2 and IC200 (ICC: 0.92), and IC100 and IC200 (ICC: 0.94) all reflected excellent test-retest reliability.

CONCLUSION

The test-retest reliability of IOP measurements taken by patients using the iCare HOME2 self-tonometer compared with IOP measurements taken by trained operators using the iCare IC100 and IC200 tonometers was uniformly excellent (ICCs all ≥0.9). These findings indicate that these three devices should be considered interchangeable for the clinical assessment of circadian IOP.

Agreement of Serial iCare HOME2 and Goldmann Applanation Tonometry

PURPOSE

To assess agreement of iCare HOME2 and Goldmann applanation tonometry over a wide range of intraocular pressure (IOP).

DESIGN

A prospective, observational cohort study.

SUBJECTS

Twenty-six adult patients undergoing intravitreal injection, which temporarily raises IOP, were recruited from the Palo Alto Medical Foundation Retina Clinic between October 2022 and February 2023.

METHODS

Subjects had serial iCare HOME2 (IOPI) and Goldmann applanation (IOPG) IOP measurements before and at 0 and 5 to 10 minutes after injection. Baseline IOPs and pachymetry were taken in both eyes.

MAIN OUTCOME MEASURES

Correlation between IOPI and IOPG was tested by within-subjects intraclass correlation coefficient (ICC) for repeated measures. Agreement between IOPI and IOPG was evaluated by a Bland-Altman plot with correction for multiple measurements. The difference between IOPI and IOPG was evaluated between eyes at baseline (Pearson's r) and within the injected eye over different timepoints (ICC for absolute agreement). Linear regression was used to evaluate the effects of age, sex, glaucoma, and corneal thickness.

RESULTS

The mean IOPI and IOPG were 25.3 (range: 9-55) and 23.5 (range: 8-56) mmHg, respectively. The correlation between IOPI and IOPG was 0.99 (P < 0.001). The mean difference (IOPG - IOPI) was 2.2 mmHg (95% limits of agreement: -3.4 to 7.8 mmHg). The bias in measurements was correlated between eyes (r, 0.68; P < 0.001) and in the injected eye across all timepoints (ICC, 0.86; 95% CI, 0.75-0.93), but did not show a relationship with age, sex, glaucoma, or corneal thickness.

CONCLUSIONS

IOPI and IOPG showed excellent correlation; however, there was a stable bias toward IOPG being higher than IOPI over a large range of IOP.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Novel Technologies in Artificial Intelligence and Telemedicine for Glaucoma Screening

PURPOSE

To provide an overview of novel technologies in telemedicine and artificial intelligence (AI) approaches for cost-effective glaucoma screening.

METHODS/RESULTS

A narrative review was performed by summarizing research results, recent developments in glaucoma detection and care, and considerations related to telemedicine and AI in glaucoma screening. Telemedicine and AI approaches provide the opportunity for novel glaucoma screening programs in primary care, optometry, portable, and home-based settings. These approaches offer several advantages for glaucoma screening, including increasing access to care, lowering costs, identifying patients in need of urgent treatment, and enabling timely diagnosis and early intervention. However, challenges remain in implementing these systems, including integration into existing clinical workflows, ensuring equity for patients, and meeting ethical and regulatory requirements. Leveraging recent work towards standardized data acquisition as well as tools and techniques developed for automated diabetic retinopathy screening programs may provide a model for a cost-effective approach to glaucoma screening.

CONCLUSION

Leveraging novel technologies and advances in telemedicine and AI-based approaches to glaucoma detection show promise for improving our ability to detect moderate and advanced glaucoma in primary care settings and target higher individuals at high risk for having the disease.

The Effect of Yoga on Intraocular Pressure Using the "iCare HOME2" Tonometer

BACKGROUND

Various yoga positions may have an unfavorable impact on intraocular pressure (IOP) and may therefore be seen as a potential risk factor for the progression of glaucoma. The new "iCare HOME2" is a handheld self-tonometer for IOP measurements outside clinical settings. This is the first study to evaluate the immediate effect of common yoga postures on the IOP of healthy and glaucomatous eyes using the "iCare HOME2" self-tonometer and to compare the time of IOP recovery in both groups.

METHODS

This is a single-center, prospective, observational study including 25 healthy and 25 glaucoma patients performing the following yoga positions: "legs up" (Viparita Karani), "bend over" (Uttanasana), "plough pose" (Halasana), and the "down face dog" (Adho Mukha Svanasana) for 90 s each, with a 2-min break in between. IOP was measured with the "iCare HOME2" before, during, and after each position.

RESULTS

IOP significantly increased in all eyes in all positions (p < 0.05), showing no statistically significant difference between healthy or glaucomatous eyes (p > 0.05). The mean rise in IOP in healthy subjects was 1.6 mmHg (SD 1.42; p = 0.037), 14.4 mmHg (SD 4.48; p < 0.001), 7.5 mmHg (SD 4.21; p < 0.001), and 16.5 mmHg (SD 3.71; p < 0.001), whereas in glaucoma patients, IOP rose by 2.8 mmHg (SD 2.8; p = 0.017), 11.6 mmHg (SD 3.86; p < 0.001), 6.0 mmHg (SD 2.24; p < 0.001), and 15.1 mmHg (SD 4.44; p < 0.001) during the above listed yoga positions, repsectively. The highest increase in IOP was seen in the down face position, reaching mean IOP values above 31 mmHg in both study groups. IOP elevation was observed immediately after assuming the yoga position, with no significant change during the following 90 s of holding each pose (p > 0.05). All IOP values returned to baseline level in all individuals, with no significant difference between healthy and glaucoma participants.

CONCLUSION

Our data show that common yoga positions can lead to an acute IOP elevation of up to 31 mmHg in healthy as well as glaucoma eyes, with higher IOP values during head-down positions. Given that IOP peaks are a major risk factor for glaucomatous optic neuropathy, we generally advise glaucoma patients to carefully choose their yoga exercises. If and to what extent practicing yoga leads to glaucoma progression, however, remains unclear and warrants further research.

Difficult decisions, filtration surgery, and the heartbreak of the numerator

A 70-year-old man had progressive and severe glaucoma in each eye. He was intolerant to dorzolamide, brimonidine, and netarsudil. Each eye had prior selective laser trabeculoplasty (SLT) as well as phacoemulsification plus minimally invasive glaucoma surgery (MIGS) 6 years before current presentation (iStent [Glaukos Corp.] in the right eye and Cypass [Alcon Laboratories, Inc.] in the left eye). Postoperative acuities were 20/20 and 20/25 in the right and left eyes, respectively. When his left eye progressed with loss of central acuity despite peak intraocular pressures (IOPs) in the middle to upper teens, neuro-ophthalmology consultation was obtained (Figure 1JOURNAL/jcrs/04.03/02158034-202401000-00017/figure1/v/2023-12-22T124801Z/r/image-tiff). That workup included magnetic resonance imaging scan and hematologic screening, but all results were negative, and the neuro-ophthalmic consultant concluded that the vision loss was likely on the basis of glaucoma. Accordingly, a trabeculectomy was performed in the left eye achieving consistent IOPs in the range of 7 to 10 mm Hg without medications, rending the left eye stable since the filtration surgery nearly 2 years previously. The right eye continued to progress both subjectively and objectively, and on recent examination, the IOP measured 20 mm Hg and 09 mm Hg in the right and left eyes, respectively (Figure 2JOURNAL/jcrs/04.03/02158034-202401000-00017/figure2/v/2023-12-22T124801Z/r/image-tiff). Medications included timolol and latanoprostene bunod in the right eye only. Central corneal thickness was 526 μm and 527 μm in the right and left eyes, respectively. The visual acuity now measured 20/25 in the right eye and 20/250 in the left eye. The vertical cup-to-disc ratio was 0.9 in the right eye and 1.0 in the left eye. Gonioscopy revealed a wide open angle in each eye with a patent sclerostomy superiorly in the left eye. The conjunctiva and sclera were healthy and without scarring in the right eye. The bleb in the left eye was diffuse, lightly vascularized, and seidel negative. Axial length (AL) was 26.88 μm in the right eye and 26.77 μm in the left eye. The patient was in good health and was not anticoagulated. An extensive discussion ensued about the best course of action for the right eye. How would you proceed in managing definite progression in this individual's right eye, knowing that he had lost fixation in his left eye at similar pressures?

Early diagnostics and interventional glaucoma

The glaucoma treatment paradigm is starting to change from a more reactive approach that relies on topical medications to a more proactive approach that leverages procedural interventions. This evolution toward interventional glaucoma has been enabled by a growing array of lower-risk minimally invasive procedures such as laser trabeculoplasty, minimally invasive glaucoma surgery, and procedural pharmaceuticals. A common feature of these glaucoma interventions-as with all glaucoma interventions-is the need for early, prompt, and accurate diagnosis. The present review summarizes new and upcoming developments in glaucoma diagnostics. These include technologies and techniques for home-based intraocular pressure measurement, novel visual field platforms, photography- and optical coherence tomography-based visualization, and artificial intelligence applications. They also include emerging technologies such as mitochondrial flavoprotein fluorescence imaging, detection of apoptosing retinal cells, collector channel visualization, and genetic testing. These diagnostic modalities have the potential to circumvent the limitations of traditional diagnostic methods. By increasing the frequency and feasibility of obtaining valuable glaucoma data with more rapid detection of disease and progression, these diagnostics may enable an interventional approach to glaucoma treatment for the betterment of patient care.

Assessment of the iCare HOME2, a New Intraocular Pressure Self-Measurement Tonometer

PRCIS

The iCare HOME2 tonometer generally can be considered reliable for most eyes and clinical settings, although it may produce slightly overestimated or underestimated intraocular pressure (IOP) readings in thicker and thinner corneas, respectively.

PURPOSE

To evaluate the accuracy, correlation, and analysis of differences in IOP measurements between the gold standard Goldmann applanation tonometer (GAT) and the new, self-measurement iCare HOME2 tonometer (icare).

PATIENTS AND METHODS

In this retrospective study, patients were randomly selected from those who attended a routine examination in our clinic. After a complete ocular examination, each patient's IOP was measured and recorded with GAT and iCare HOME2. Central corneal thickness was measured. Eyes with any corneal morbidity were excluded. Pearson correlation coefficient was used to determine the correlation between paired IOP measurements. Bland-Altman plots were graphed for the analysis of differences in IOP between the instruments.

RESULTS

One hundred thirty-five eyes of 70 patients were included in the study. The mean IOP measured with GAT was 16.3 ± 6.5 mm Hg (range: 3-56). The mean IOP measured with iCare HOME2 was 16.5 ± 7.3 mm Hg (range: 3-55), ( P = 0.47). A strong, significant positive correlation was found for paired IOP measurements by the 2 instruments ( r = 0.94; P < 0.0001). A small systematic proportional bias was seen for the paired IOP measurements, meaning that with higher IOPs the iCare HOME2 yielded higher IOP readings than GAT, but this difference was clinically insignificant. The instrument underestimated IOPs with corneas thinner than 522 µm, whereas it overestimated IOPs when corneas were thicker than this.

CONCLUSION

The iCare HOME2 could be a reliable tonometer for most eyes and clinical settings. Central corneal thickness measurement is recommended in patients who use the instrument.

Clinical utility, feasibility of home tonometry using iCare HOME by glaucoma patients

Purpose

To determine agreement between diurnal variation testing (DVT) of intraocular pressure (IOP) with Goldmann applanation tonometer (GAT) and iCare HOME (IH) by an optometrist (OP) and home monitoring by participants (PT).

Methods

Patients (18-80 years) with glaucoma and suspects were enrolled. IH IOP and GAT were taken by an OP at 2 h intervals from 8 AM to 4 PM on Day 1 and PT between 6 AM and 9 PM, for the next 2 days. IOP, date, and time were viewed via iCare LINK software.

Results: In total,

72.9.

(

51/70) PT trained were able to take reliable readings. One hundred two eyes (51 patients, age 53 ± 16 yrs) were analyzed. Correlation between optometrist (OP) and participants (PT) was strong and positive {IH OP-IH PT- r = 0.90, p-0.0001;IH PT-GAT- r = 0.79, p-0.0001}. Agreement by Bland Altman plots was limited {IH OP-IH PT mean 0.1 mmHg (95% LOA -5.3 to 5.5), IH PT-GAT 2.2 mmHg (-5.7 to 10.1)}. Intraclass correlation coefficient for IH OP-IH PT was 1.18 (95% CI 1.37-1.09). Intradevice {0.95 (95% CI 0.94-0.97)} and interrater repeatability {0.91 (0.79-0.96)} were good. 37% of eyes had a synchronous peak on GAT and IH during the day DVT.

Conclusion

Home tonometry by iCare HOME is easy, feasible, but due to limited agreement cannot substitute GAT DVT.

Repeated Measurements Are Necessary for Evaluating Accurate Diurnal Rhythm Using a Self-Intraocular Pressure Measurement Device

PURPOSE

To investigate how many tests need to be performed to adequately assess intraocular pressure (IOP) diurnal change using a self-measuring rebound tonometer among glaucoma patients.

SUBJECTS AND METHODS

Adult patients with primary open-angle glaucoma were included. IOP was measured in the morning (6 AM to 9 AM), afternoon (12 PM to 3 PM), and at night (6 PM to 9 PM) for seven consecutive days. Twenty-four (7 males and 17 females, mean age 59.5 ± 11.0 years) patients who successfully measured IOP at least three times per day during the correct time periods for four days were subjected to analysis.

RESULTS

The IOP rhythm was significantly greater on the first day of measurement (6.6 ± 3.6 mmHg) than that averaged during subsequent days (4.4 ± 2.2 mmHg). The time of the highest and lowest IOP measurements on the first day of IOP measurement and during the entire measurement period coincided in 72.9% and 64.6% of cases, respectively. The concordance rate of the highest IOP time between the whole measurement period and each measurement day was less than 60%.

CONCLUSION

The diurnal IOP rhythm measured by the patients themselves was not consistent, and multiple days of measurements may be necessary to correctly assess diurnal IOP rhythm.

Home Monitoring of Glaucoma Using a Home Tonometer and a Novel Virtual Reality Visual Field Device: Acceptability and Feasibility

OBJECTIVE

Our aim was to assess the acceptability and feasibility of iCare HOME tonometer (HT) and Virtual Field (VF) devices in the home monitoring of glaucoma.

DESIGN

Prospective feasibility and acceptability study.

SUBJECTS

Twenty patients (39 eyes) with primary open-angle glaucoma, open-angle glaucoma, ocular hypertension, or suspected glaucoma.

METHODS

Patients were trained and instructed to bring 2 devices home for 1 week and use the HT 4 times/day for 4 days and the VF 3 times total.

MAIN OUTCOME MEASURES

For acceptability, we conducted satisfaction surveys and semistructured, qualitative interviews with a thematic analysis. Feasibility was assessed by device usage and quality of tests.

RESULTS

Most patients (73.7%) felt that the HT was easy to use, and 100% of them found the HT useful. All patients (100%) felt that VF was easy to use, and 94.4% of them found the VF useful. All patients (100%) obtained acceptable intraocular pressure and completed a VF test at home. We identified 4 key themes, with 33 subthemes. The key themes include the following: (1) advantages of home monitoring; (2) difficulties with home monitoring; (3) future considerations in home monitoring; and (4) the experience of patients with glaucoma.

CONCLUSIONS

The HT and VF were acceptable and feasible in a small cohort of motivated subjects. Patients were able to perform these tests proficiently at home, and they were generally enthused to obtain more data about their intraocular health, as it allowed them a heightened sense of security and insight about their chronic disease, as well as a reduction in foreseeable barriers to care. Home monitoring may also improve upon glaucoma care by enhancing patient empowerment and fostering community bonds. The VF should be further evaluated to ensure validity.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

[Tonometry: Review and Perspectives]

Reliable and repeated IOP measurement are essential in the diagnosis and treatment of glaucoma. In this second part, the other contact tonometry and non-contact tonometry are presented. The clinical value of the different methods and the value of multimodality in tonometry will be discussed based on a review of the literature, and the latest innovations with telemetric IOP sensors will be introduced.

Tonometrie: Rückblick und Ausblick (Teil 2)

In 2. Teil des Beitrags werden die sonstigen Kontakttonometer und die Nonkontakttonometrie präsentiert. Es wird anhand einer Revue der Literatur über den klinischen Wert der verschiedenen Methoden und den Wert der Multimodalität in der Tonometrie diskutiert; ferner werden die letzten Innovationen mit den telemetrischen IOD-Sensoren eingeführt.

Perspectives on the Home Monitoring of Macular Disease

Recent advancements in imaging technology have led to increasing interest in home monitoring of macular disease. The prevalence of macular disease is projected to rise considerably over time, leading to a significant burden on hospital services for age-related macular degeneration and diabetic macular edema. Home monitoring has the potential to augment conventional hospital assessment and so enable improved access to clinical care for low- and moderate-risk patients, while also allowing sensitive detection of early signs of disease that may require prompt intervention. Despite this, there are significant considerations before large-scale implementation could be possible. These are related to both the current availability of home monitoring technology and the logistical barriers to its widespread introduction. Access to home monitoring is also likely to be more challenging in lower-income communities and countries, with subsequent implications for health inequality that will need to be considered and addressed appropriately.

iCare® Home vs Goldmann applanation tonometry: Agreement of methods and comparison of inter-observer variation at a tertiary eye centre

Purpose: To investigate whether the inter-observer variation is similar between the Goldmann applanation tonometer used by healthcare staff and the iCare® Home tonometer used by glaucoma patients, volunteers and healthcare staff. Methods: Sixty-one participants were recruited to the study, including 24 glaucoma patients. Seven participants were excluded. For each participant, intraocular pressure (IOP) was measured on the same occasion by two different healthcare staff using GAT as well as by a healthcare staff and the participant using the iCare® Home tonometer. Results: Seventy-two per cent of iCare® measurements were within 3 mmHg of the GAT measurements. There was a statistically significant difference between the trainers' measurements made with iCare® Home and those made with GAT (p < 0.001), as well as between the GAT measurements made by trainers and those made by extra personnel (p = 0.017). The strongest correlation was between iCare® Home participants' and trainers' measurements (0.934). The correlation between different users with GAT was lower (0.769). The inter-user agreement was excellent for iCare® Home users (95% CI 0.93, ranging from 0.880 to 0.959) and moderate for GAT users (95% CI 0.741, ranging from 0.558 to 0.849). Conclusion: Our study found that tonometry with iCare® Home has similar or less inter-user variation compared with GAT.

Deployment of the Water Drinking Test and iCare HOME Phasing for Intraocular Pressure Profiling in Glaucoma Evaluation

SIGNIFICANCE

Intraocular pressure (IOP) profiling is an important component of the glaucoma examination. Two techniques for profiling are the water drinking test (WDT) and iCare HOME phasing, but the correlations between techniques and their ease of deployment have not been studied. These questions are important in determining suitability for clinical deployment.

PURPOSE

This study aimed to compare the IOP results of the WDT and iCare HOME phasing in patients with suspected or newly diagnosed glaucoma.

METHODS

Ninety-eight consecutive patients attending a glaucoma clinic underwent IOP profiling using both techniques. For the WDT, patients ingested 10 mL/kg body weight of water after a baseline applanation IOP measurement and then underwent serial IOP measurements approximately every 15 minutes, ceasing after 30 minutes of consecutive measurements within 3 mmHg of baseline. Patients successfully certified for self-administration of the iCare HOME were loaned the instrument for 1 week and instructed to take four measurements per day.

RESULTS

Twenty-seven patients (28%) successfully obtained four measurements per day using iCare HOME, and 96 patients (98%) were able to complete the WDT. Intraocular pressure profiles showed no difference between the time for peak IOP and across nearly all IOP parameters obtained from profiling except for the standard deviation of IOP measurements obtained using the iCare HOME (P = .005). There were moderate correlations between peak IOPs obtained using each technique (r = 0.67, P = .001, right eye; r = 0.66, P = .002, left eye) but no correlation between the daily range (iCare HOME) or peak-trough difference (WDT; r = 0.21, P = .28, right eye; r = 0.27, P = .02, left eye). Bland-Altman analysis returned similar results for peak and range.

CONCLUSIONS

Intraocular pressure profiling using both techniques can reveal the peak IOP, and these measurements are strongly correlated. Most patients were unable to complete the iCare HOME according to the manufacturer's recommendations. Clinicians should select the most appropriate technique for each patient.

Measures of disease activity in glaucoma

Glaucoma is the leading cause of irreversible blindness globally which significantly affects the quality of life and has a substantial economic impact. Effective detective methods are necessary to identify glaucoma as early as possible. Regular eye examinations are important for detecting the disease early and preventing deterioration of vision and quality of life. Current methods of measuring disease activity are powerful in describing the functional and structural changes in glaucomatous eyes. However, there is still a need for a novel tool to detect glaucoma earlier and more accurately. Tear fluid biomarker analysis and new imaging technology provide novel surrogate endpoints of glaucoma. Artificial intelligence is a post-diagnostic tool that can analyse ophthalmic test results. A detail review of currently used clinical tests in glaucoma include intraocular pressure test, visual field test and optical coherence tomography are presented. The advanced technologies for glaucoma measurement which can identify specific disease characteristics, as well as the mechanism, performance and future perspectives of these devices are highlighted. Applications of AI in diagnosis and prediction in glaucoma are mentioned. With the development in imaging tools, sensor technologies and artificial intelligence, diagnostic evaluation of glaucoma must assess more variables to facilitate earlier diagnosis and management in the future.

How to Measure Intraocular Pressure: An Updated Review of Various Tonometers

Intraocular pressure (IOP) is an important measurement that needs to be taken during ophthalmic examinations, especially in ocular hypertension subjects, glaucoma patients and in patients with risk factors for developing glaucoma. The gold standard technique in measuring IOP is still Goldmann applanation tonometry (GAT); however, this procedure requires local anesthetics, can be difficult in patients with scarce compliance, surgical patients and children, and is influenced by several corneal parameters. Numerous tonometers have been proposed in the past to address the problems related to GAT. The authors review the various devices currently in use for the measurement of intraocular pressure (IOP), highlighting the main advantages and limits of the various tools. The continuous monitoring of IOP, which is still under evaluation, will be an important step for a more complete and reliable management of patients affected by glaucoma.

Home Monitoring for Glaucoma: Current Applications and Future Directions

Technological advances provide a number of options for glaucoma monitoring outside the office setting, including home-based tonometry and perimetry. This has the potential to revolutionize management of this chronic disease, improve access to care, and enhance patient engagement. Here, we provide an overview of existing technologies for home-based glaucoma monitoring. We also discuss areas for future research and the potential applications of these technologies to telemedicine, which has been brought to the forefront during the ongoing COVID-19 pandemic.