The Icare HOME (TA022) Study: Performance of an Intraocular Pressure Measuring Device for Self-Tonometry by Glaucoma Patients

Evaluation of a new transpalpebral tonometer for self-measuring intraocular pressure

PURPOSE

We developed a novel transpalpebral self-tonometer called the TapEye tonometer (TET) based on palpation of the upper eyelid. Our goal was to evaluate a method for improving the accuracy of measuring intraocular pressure (IOP) through the eyelid.

METHODS

Participants underwent standardized training by technicians and were required to be able to use the TET for study inclusion. Subsequently, a noncontact tonometer and Goldmann applanation tonometer (GAT) were used. All participants were instructed to measure their IOPs using the three tonometers at baseline (visit 1) and at 1 month (visit 2). At visit 2, the corrected IOP value measured by the TET (c-TET) was calculated using the difference between the TET and GAT measurements obtained at visit 1.

RESULTS

No significant correlations were found between the TET and GAT measurements at any visit, but the correlation between the c-TET and GAT measurements at visit 2 was significant. The mean difference between the c-TET and GAT measurements was 0.4 ± 3.7 mmHg in the right eye and 0.5 ± 3.4 mmHg in the left eye.

CONCLUSIONS

After correcting the IOP based on the difference between the TET and GAT measurements at the initial visit, the corrected IOP value of the TET was correlated with that of the GAT at the second visit. The TET has the potential to address an unmet need by providing a tool for minimally invasive IOP measurements.

TRIAL REGISTRATION

Clinical trial registration number: jRCTs032220268.

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.

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.

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.

Recent developments of telemedicine in glaucoma

PURPOSE OF REVIEW

Telemedicine has an increasingly significant role in the fields of ophthalmology and glaucoma. This review covers recent advancements in the development and optimization of teleglaucoma techniques and applications.

RECENT FINDINGS

Glaucoma monitoring and diagnosis via remote tonometry, perimetry, and fundus imaging have become a possibility based on recent developments. Many applications work in combination with smart devices, virtual reality, and artificial intelligence and have been tested in patient populations against conventional "reference-standard" measurement tools, demonstrating promising results. Of note, there is still much progress to be made in teleglaucoma and telemedicine at large, such as accessibility to internet, broadband, and smart devices, application affordability, and reimbursement for remote services. However, continued development and optimization of these applications suggest that the implementation of remote monitoring will be a mainstay for glaucoma patient care.

SUMMARY

Especially since the beginning of the COVID-19 pandemic, remote patient care has taken on an important role in medicine and ophthalmology. Remote versions of tonometry, perimetry, and fundus imaging may allow for a more patient-centered and accessible future for glaucoma 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.

Performance of home-based self-tonometry (iCare HOME (TA022)) for measuring intraocular pressure among healthy and glaucoma patients

Introduction: The purpose of this study was to compare iCare HOME (TA022) with Goldmann applanation tonometer and to evaluate the self-tonometry measurements among the Indian population. Methods: Eligible patients underwent iCare HOME training through guided demonstration (verbal, pictorial, video) and practised self-tonometry measures using iCare HOME. Certification for independent iCare HOME measure was provided if first iCare HOME intraocular pressure (IOP) measurement fell within ± 5 mmHg of Goldmann applanation tonometer (GAT) measurement which was measured by the trained clinician (principal investigator). Certified participants underwent simulated home self-tonometry measurements using iCare HOME, and agreement with GAT IOP measurements was assessed. Results: Seven of 83 participants (8.43%) failed to complete the study due to difficulty in performing the task, leading to non-certification. Patients who could use the iCare HOME had a mean age of 53 ± 15.55years (53% males; 46% females). Only one in 12 subjects did not qualify to use iCare HOME. The overall mean difference between iCare HOME and GAT was 0.83 mmHg (95%, 3.92 and -2.25). At various pressure ranges, 7-16 mmHg, 17-23 mmHg and >23 mmHg, the mean difference between iCare HOME and GAT was 1.22 mmHg (95%, 4.32 and -1.86), 0.77 mmHg (95%,3.69 and -2.19), -0.11 mmHg (95%, 2.52 and -2.74) respectively. The intra-class correlation coefficient of the iCare HOME device was 0.997(95% CI,0.995-0.998). Conclusions: Patients were able to perform self- tonometry using iCare HOME with good reliability and safety. iCare HOME can be used to address the issue of difficulty in acquiring frequent and diurnal IOP measurements by patients doing self-tonometry from home.

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.

Assessment of intraocular pressure measurement between Goldman applanation tonometer, rebound tonometer, non-contact tonometer, and its correlation with central corneal thickness

Purpose

To compare readings of intraocular pressure (IOP) taken with the Goldmann applanation tonometer (GAT), the non-contact tonometer (NCT), and the rebound tonometer (RBT), and to compare their correlation with central corneal thickness (CCT).

Methods

This was a prospective, cross-sectional, observational study to which patients above 18 years of age were enrolled. A total of 400 eyes of 200 non-glaucomatous patients underwent IOP recordings using the GAT, NCT, and RBT, and CCT was also noted. Informed consent of the patients was taken. The IOP readings taken via the three methods were compared and correlated with CCT. Paired t test was used to compare the two devices. Simple and multivariate linear regression analyses were used to study the relationship between factors. A P value less than 0.05 was considered significant. Correlation was determined using the Pearson correlation coefficient, and a Bland-Altman graph was plotted.

Results

Mean IOP measured by the NCT was 15.65 ± 2.80 mmHg, by the RBT was 14.23 ± 3.05 mmHg, and by the GAT was 14.69 ± 2.97 mmHg. The mean CCT was 510.61 ± 33.83 microns. The difference between mean IOP recorded by the NCT and that by the RBT was 1.41 ± 2.39 mmHg, between the NCT and GAT was 0.95 ± 2.03 mmHg, and between the GAT and RBT was 0.45 ± 2.22 mmHg. The difference between the IOP values was statistically significant (P < 0.005). All tonometers showed a statistically significant correlation with CCT, but it was observed that the NCT had a stronger correlation (0.4037).

Conclusion

The IOP readings taken by all the three methods were comparable; however, RBT values were closer to GAT values. CCT did influence the IOP values, and this should be kept in mind while evaluating.

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.

Impact of self-tonometry on glaucoma treatment decision

PURPOSE

The aim of this study was to examine the impact of self-tonometry on clinicians' decision in glaucoma treatment.

MATERIALS AND METHODS

Medical records of 133 patients who had performed self-tonometry using iCare^® Home between January and December 2019 were retrospectively reviewed. Inclusion criteria were as follows: age over 18 years, all types of glaucoma, as well as ocular hypertension and glaucoma suspect, compliance with tonometer manufacturer's recommendations and monitoring over at least 2 days. The data consisted of age, gender, diagnosis, visual field index, rate of progression and type of treatment pre- and post-intraocular pressure (IOP) phasing. The following IOP measurements were used to calculate the mean and maximum IOP, and range over each day and consecutive days: Goldmann applanation tonometry (GAT) measurements from referral and training visits and iCare^® Home measurements made by the trainers and the patients themselves. A total of 90 patients were included.

RESULTS

Clinicians were satisfied with the actual treatment in 54.4% of the cases. There was a statistically significant difference between the clinicians' decision to maintain same treatment or to escalate therapy for all the mean and maximum IOPs measured on each single day and over a 2- or 3-day period (p < 0.002).

CONCLUSION

Our results suggest that the presence of high IOP values obtained with self-tonometry supports an intensification of glaucoma treatment. Self-tonometry provides clinicians with an important complement for clinical decision-making, and under- or over-treatment may be avoided for the benefit of patients.

EYEMATE-SC Trial: Twelve-Month Safety, Performance, and Accuracy of a Suprachoroidal Sensor for Telemetric Measurement of Intraocular Pressure

PURPOSE

Measuring and controlling intraocular pressure (IOP) provide the foundation for glaucoma treatment. Self-tonometry has been proposed as an alternative to measure IOP throughout the entire day better. The novel EYEMATE-SC sensor (Implandata) is implanted in the suprachoroidal space to enable contactless continual IOP monitoring. The aim of the present study was to investigate the 1-year safety, performance, and accuracy of the EYEMATE-SC in patients with primary open-angle glaucoma undergoing simultaneous nonpenetrating glaucoma surgery (NPGS).

DESIGN

Prospective, multicenter, open-label, single-arm, interventional clinical trial.

PARTICIPANTS

Twenty-four eyes of 24 patients with primary open-angle glaucoma who were due to undergo NPGS (canaloplasty or deep sclerectomy).

METHODS

An EYEMATE-SC sensor was implanted during NPGS. Goldmann applanation tonometry (GAT) measurements were compared with the sensors' IOP measurements at all postoperative visits through 12 months.

MAIN OUTCOME MEASURES

Device position and adverse events.

RESULTS

Fifteen eyes underwent canaloplasty, and 9 underwent deep sclerectomy. Successful implantation of the sensor was achieved in all eyes with no reported intraoperative difficulties. Through the 12-month follow-up, no device migration, dislocation, or serious device-related complications were recorded. A total of 536 EYEMATE-SC measurements were pairwise included in the IOP agreement analysis. The overall mean difference between GAT and EYEMATE-SC measurements was 0.8 mmHg (95% confidence interval [CI] of the limits of agreement [LoA], -5.1 to 6.7 mmHg). The agreement gradually improved, and from 3 months after surgery until the end of the follow-up, the mean difference was -0.2 mmHg (95% CI of LoA, -4.6 to 4.2 mmHg) over a total of 264 EYEMATE-SC measurements, and 100% of measurements were within ±5 mmHg of GAT.

CONCLUSIONS

The EYEMATE-SC sensor was safe and well tolerated through 12 months. Moreover, it allowed accurate, continuous IOP monitoring.

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.

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.

The utility of home tonometry for peri-interventional decision-making in glaucoma surgery: Case series

Purpose

To describe twelve cases in which home intraocular pressure (IOP) monitoring complimented clinical decision-making in glaucoma management.

Observations

Home IOP monitoring elucidated peaks and amplitudes of variation that were not captured by in-clinic IOP measurements during the pre- or post-interventional period.

Conclusions & Importance

Home monitoring can establish pre-treatment IOP patterns that are not evident during in-clinic measurements. Home monitoring can also demonstrate response to treatment more quickly than in-clinic monitoring, and provide more information about nyctohemoral fluctuations than is ascertained by in-clinic tonometry.

Accuracy and Reliability of Self-measured Intraocular Pressure in Glaucoma Patients Using the iCare HOME Tonometer

PRCIS

The iCare HOME tonometer is a useful tool which can be used by patients for fairly accurate and reliable self-measurement of intraocular pressure (IOP).

PURPOSE

The aim was to compare the accuracy of IOP measurements of trained glaucoma patients using the iCare HOME tonometer before and after a week of self-monitoring at home and study the repeatability of patient measurements done at home.

MATERIALS AND METHODS

A total of 40 glaucoma patients had IOPs measured using the Goldmann applanation tonometer and the iCare HOME. Patients were trained to use the iCare HOME and measured their IOP twice daily over a loan period of 7 days. Bland-Altman analysis was used to assess agreement between Goldmann applanation tonometer and iCare HOME readings. Intraclass correlation coefficient compared inter-rater reliability of iCare HOME measurements, and test-retest variability for the patient's readings over the 7-day period were analyzed. A 5-point Likert scale questionnaire was used to assess the patient's experience with the device.

RESULTS

Up to 32 patients (80%) were able to obtain IOP readings within 3 mm Hg of the glaucoma nurse clinician's readings at the preloan visit, and up to 36 patients (90%) at the postloan visit. Good inter-rater reliability was observed between iCare HOME measurements by the glaucoma nurse clinician and patients. At the postloan visit, inter-rater reliability was good for right eye readings and excellent for left eye readings. No distinct trend in test-retest variability was identified over the 7-day period. 65% of patients agreed the device was easy to use and 89% would recommend the device to other glaucoma patients.

CONCLUSION

Patients trained to use the iCare HOME device can do so with fair accuracy compared with trainers with accuracy improving within 1 week of usage.

Clinical Trial: Diurnal IOP Fluctuations in Glaucoma Using Latanoprost and Timolol with Self-Tonometry

SIGNIFICANCE

Assessment of treatment efficacy via comparison with a target IOP is fundamental in monitoring patients with open-angle glaucoma and ocular hypertension. This article highlights that diurnal IOP fluctuations obtained using self-tonometry may more accurately reflect IOP responses to therapy.

PURPOSE

This study aimed to investigate fluctuations in diurnal IOP measurements in patients with open-angle glaucoma and ocular hypertension treated with latanoprost 0.005% and timolol 0.25%.

METHODS

In this crossover treatment trial, 14 participants performed self-tonometry with iCare HOME 4 times daily for (1) 1 week using latanoprost, (2) 4 weeks using no medications, and (3) 2 weeks using timolol. Daily peak IOPs, IOP fluctuations, and mean IOPs from different treatments were compared on an individual basis. Treatment efficacy between medications was assessed by comparing mean percentage IOP reductions with latanoprost and timolol across participants. In addition, effects of age, years since commencing latanoprost, sex, and diagnosis were investigated, and peak IOP times were compared with assess impacts on diurnal profiles.

RESULTS

Between individuals, IOP responses ranged from reductions in peak IOPs, IOP fluctuations, and mean IOPs on both medications to no change in any parameter and medication. IOP fluctuations showed greater mean percentage reductions than did peak and mean IOPs (χ2 = 16.51, P = .002). There were significant associations between years since commencing latanoprost and peak and mean IOP responses on timolol (r = 0.69, P = .007), and sex and relative reductions in IOP fluctuations on both medications (P = .03). There were no differences in peak IOP times between treatment conditions.

CONCLUSIONS

Despite variability in IOP responses to latanoprost and timolol, IOP fluctuation with self-tonometry was more consistent in evaluating target IOP, reflecting its importance in ascertaining true IOP response to topical therapies. These findings may impact clinical decision making based on target IOP criteria in patients on topical therapy.

The Utility of iCare HOME Tonometry for Detection of Therapy-Related Intraocular Pressure Changes in Glaucoma and Ocular Hypertension

PURPOSE

To assess whether iCare HOME rebound tonometry can detect therapy-related changes during self-monitoring of intraocular pressure (IOP).

DESIGN

Prospective clinical trial.

PARTICIPANTS

A total of 43 eyes (n = 27 subjects) with open-angle glaucoma or ocular hypertension were enrolled during standard-of-care clinic visits. Participants were grouped into control eyes managed on stable therapy (n = 18 eyes) or therapy change eyes undergoing selective laser trabeculoplasty (SLT, n = 8 eyes), initiating topical therapy (n = 8 eyes), or adding a second medication to existing monotherapy (n = 9 eyes).

METHODS

Subjects recorded IOP 4 times daily for 1 week using iCare HOME tonometry. Upon tonometer return, subjects underwent SLT or new medication start; an additional week of iCare HOME measurements was collected after 4 to 6 weeks. Control subjects recorded an additional week of measurements after 6 weeks. Measurements were grouped into 4 time periods (5-10 am, 10 am to 3 pm, 3-8 pm, 8 pm to 1 am). Goldmann applanation tonometry (GAT) was performed at each study visit for comparison.

MAIN OUTCOME MEASURES

Detection of therapy response defined as an IOP reduction of ≥20%.

RESULTS

For eyes that demonstrated a therapy response by GAT (n = 11), iCare HOME detected a therapy response in 90.9% of eyes in ≥1 time period and 45.5% of eyes in all 4 time periods. In eyes without a GAT-measured therapy response (n = 14), iCare HOME detected a response for 71.4% (n = 10) of eyes in ≥1 time period and for 7.1% of eyes (n = 1) at all 4 time periods. In treatment eyes, intraday and interday average minimum and maximum IOP, as well as interday IOP range, were significantly reduced after therapy without a significant change in intraday IOP range. Control group eyes did not demonstrate a significant change in average IOP minimum, maximum, or range between study weeks.

CONCLUSIONS

Home tonometry with iCare HOME reliably detects therapy-related IOP changes in patients with glaucoma and ocular hypertension. Treatment responses correlated well with in-office GAT and may detect treatment responses missed by GAT. Intraocular pressure measurements via home tonometry provide additional clinical information regarding intraday and interday IOP fluctuation beyond standard of care in office GAT measurements. The iCare HOME is a valuable tool to monitor therapeutic efficacy in patients with glaucoma.

Home Self-tonometry Trials Compared with Clinic Tonometry in Patients with Glaucoma

PURPOSE

This study examined characteristics of intraocular pressure (IOP) as measured during home tonometry in comparison with in-clinic tonometry in patients with glaucoma.

DESIGN

Retrospective cross-sectional study of glaucoma patients who completed 1 week of self-tonometry at a single academic center.

PARTICIPANTS

Patients with glaucoma who completed home tonometry trials with the iCare HOME tonometer (iCare USA) for any reason.

METHODS

Home IOP measurements were compared with in-clinic tonometry performed during the 5 visits preceding home tonometry. Maximum daily IOP was correlated to time of day. Generalized estimating equations were used to evaluate patient characteristics and clinic-derived variables that predicted differences between home and clinic IOP.

MAIN OUTCOME MEASURES

IOP mean, maximum, minimum, range, standard deviation and coefficient of variation were compared between clinic and home tonometry. IOP mean daily maximum (MDM) and mean daily range were calulated to describe recurrent IOP spiking.

RESULTS

A total of 107 eyes from 61 patients were analyzed. Mean age was 63.2 years (standard deviation [SD], 14.0 years) and 59.0% were women. Mean clinic and home IOPs were 14.5 mmHg (SD, 4.7 mmHg) and 13.6 mmHg (SD, 5.1 mmHg). Home tonometry identified significantly higher maximum IOP, lower minimum IOP, and greater IOP range than clinic tonometry (P < 0.001). Maximum daily IOP occurred outside of clinic hours (8 am-5 pm) on 50% of days assessed and occurred between 4:30 am and 8 am on 24% of days. Mean daily maximum IOP exceeded maximum clinic IOP in 44% of patients and exceeded target IOP by 3 mmHg, 5 mmHg, or 10 mmHg in 31%, 15%, and 6% of patients, respectively. Patient characteristics that predicted significant deviations between MDM and mean clinic IOP or target IOP in multivariate models included younger age, male gender, and absence of prior filtering surgery.

CONCLUSIONS

Self-tonometry provides IOP data that supplements in-clinic tonometry and would not be detectable over daytime in-clinic diurnal curves. A subset of patients in whom home tonometry was ordered by their glaucoma clinician because of suspicion of occult IOP elevation demonstrated reproducible IOP elevation outside of the clinic setting. Such patients tended to be younger and male and not to have undergone previous filtering surgery.

Fluctuation in Blood Pressure and Intraocular Pressure in Normal Tension Glaucoma Using Ambulatory Monitoring

PRCIS

Ambulatory blood pressure (BP) and intraocular pressure (IOP) monitoring of patients with normal tension glaucoma (NTG) revealed features of vascular dysregulation including hypertension, blunted nocturnal BP dipping, and morning BP surge.

PURPOSE

The aim was to examine ambulatory fluctuations in IOP and BP in patients with NTG.

METHODS

A prospective study of 45 participants with NTG and 10 controls. All participants had a comprehensive ophthalmological examination followed by glaucoma medication washout. Patients using systemic antihypertensives were excluded. IOP and BP were recorded using home monitoring over 48 hours using a self-rebound tonometer and ambulatory blood pressure monitor. BP was recorded every 30 minutes by day and every 60 minutes overnight. IOP was recorded at 09:00, 11:00, 13:00, 16:00, 20:00, and 04:00.

RESULTS

Participants with NTG had a median mean deviation (MD) of -4.66 dB (interquartile range: -7.16 to -2.81 dB) in the worse eye. Among those with glaucoma, 18 of 45 (40%) had normal nocturnal BP dipping, 24 (53%) blunted dipping and 3 (6.7%) exaggerated dipping. Each 10 mm Hg lower minimum sleeping systolic BP was associated with a 0.9 dB (95% confidence interval: 0.1-1.6 dB) worse MD. Sixteen of 45 participants with glaucoma (35.6%) and 1 of 10 controls (10%) were found to have systemic hypertension on ambulatory blood pressure monitoring and 32 of those with glaucoma (71%) had a surge in morning BP, compared with 5 controls (50%). There was no difference in MD between patients with normal, exaggerated and blunted dipping (P=0.813).

CONCLUSIONS

Though glaucoma has been associated with exaggerated nocturnal BP dipping, we found a higher proportion of patients had systemic hypertension, blunted nocturnal BP dipping, and a morning BP surge, measures also associated with vascular dysregulation.

Role of home monitoring with iCare ONE rebound tonometer in glaucoma patients management

AIM

To evaluate intraocular pressure (IOP) measurements and fluctuations using the iCare ONE rebound tonometer (RT-ONE), during home monitoring, in diagnosed and suspected glaucoma patients.

METHODS

A retrospective case series of consecutive patients with known glaucoma or glaucoma suspects who were followed-up and treated between January 2016 and January 2017. The study included 80 eyes of 40 patients with a mean age of 59.1±14.6y (range, 24-78). All patients have undergone 4-5d of IOP home monitoring with RT-ONE at morning, noon, afternoon, and night time.

RESULTS

Baseline mean IOP, as measured in the clinic (8 a.m.-12 p.m.), was 17.4±5.1 mm Hg, compared to RT-ONE home monitoring mean IOP of 15.6±4.1 mm Hg (P=0.002). Mean IOP was significantly lower at noon, afternoon and night times compared to clinic measured IOP and morning measurements (P=0.005). IOP peak measured during home monitoring was significantly higher compared to the clinic measured IOP (21.3±5.6 mm Hg and 17.4±5.1 mm Hg, P<0.001). IOP peaks during home monitoring demonstrated a majority of 47 peaks during morning measurements, compared to 23 at noon, 19 at afternoon and only 12 at night (P<0.001). The home monitoring results led to treatment modification of 44 eyes (55%), treatment regime was insufficient for 40 (50%) eyes.

CONCLUSION

Home monitoring IOP with RT-ONE can provide good assessment of mean IOP, IOP fluctuations and peaks throughout the hours of the day, which lead to an accurate treatment for glaucoma patients.

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.

Glaucoma care during the coronavirus disease 2019 pandemic

PURPOSE OF REVIEW

The current article reviews the impact of the coronavirus disease 2019 (COVID-19) pandemic on the delivery of ophthalmic, and specifically, glaucoma care.

RECENT FINDINGS

Literature from the review period includes case series demonstrating the presence of severe acute respiratory syndrome coronavirus 2 RNA in the conjunctival secretions of patients with laboratory-confirmed COVID-19. The global ophthalmology community published reports outlining the enhanced infection control measures undertaken by different institutions around the world to mitigate transmission of the novel coronavirus. Telemedicine has been increasingly implemented in glaucoma practices to reduce in-office patient volume. New data regarding the efficacy and feasibility of tools for home monitoring of intraocular pressure, virtual visual field testing, and remote disc photography are reviewed.

SUMMARY

COVID-19 has posed a global public health threat due to the severity of its contagion and associated morbidity and mortality. Glaucoma specialists have responded to the pandemic with innovative modifications to reduce viral transmission and optimize patient and staff safety in the office and operating room. The role of teleglaucoma has expanded and will continue to evolve as remote diagnostic devices undergo further refinement and validation.

Glaucoma Home Monitoring Using a Tablet-Based Visual Field Test (Eyecatcher): An Assessment of Accuracy and Adherence Over 6 Months

Purpose

To assess accuracy and adherence of visual field (VF) home monitoring in a pilot sample of patients with glaucoma.

Design

Prospective longitudinal feasibility and reliability study.

Methods

Twenty adults (median 71 years) with an established diagnosis of glaucoma were issued a tablet perimeter (Eyecatcher) and were asked to perform 1 VF home assessment per eye, per month, for 6 months (12 tests total). Before and after home monitoring, 2 VF assessments were performed in clinic using standard automated perimetry (4 tests total, per eye).

Results

All 20 participants could perform monthly home monitoring, though 1 participant stopped after 4 months (adherence: 98% of tests). There was good concordance between VFs measured at home and in the clinic (r = 0.94, P < .001). In 21 of 236 tests (9%), mean deviation deviated by more than ±3 dB from the median. Many of these anomalous tests could be identified by applying machine learning techniques to recordings from the tablets' front-facing camera (area under the receiver operating characteristic curve = 0.78). Adding home-monitoring data to 2 standard automated perimetry tests made 6 months apart reduced measurement error (between-test measurement variability) in 97% of eyes, with mean absolute error more than halving in 90% of eyes. Median test duration was 4.5 minutes (quartiles: 3.9-5.2 minutes). Substantial variations in ambient illumination had no observable effect on VF measurements (r = 0.07, P = .320).

Conclusions

Home monitoring of VFs is viable for some patients and may provide clinically useful data.

Icare Home Tonometer: A Review of Characteristics and Clinical Utility

The Icare HOME (TA022, Icare Oy, Vanda, Finland) is rebound tonometer recently approved by the US Food and Drug Administration in March 2017 designed for self-measurement of intraocular pressure (IOP). IOP remains a major modifiable risk factor for glaucoma progression; however, IOP measurements typically occur through single office measurements on Goldmann applanation tonometry (GAT) and do not always reveal the complete picture of patient’s IOP patterns and daily fluctuations, which are important for accurate diagnosis and evaluation. Numerous studies have now compared the efficacy of the Icare HOME to that of GAT. The objective of this article is to review the existing literature surrounding the Icare HOME tonometer and its efficacy as a self-tonometer in comparison to GAT. The available literature has shown promising results in its accuracy of measuring IOP but suggests cautious usage in patients with central corneal thicknesses or IOP ranges that are outside of a certain range. This article will also provide details and example cases for when the Icare HOME may be most clinically useful.

Results of First In Vivo Trial of an Acoustic Self-Tonometer

Purpose

Glaucoma is the world's most common cause of irreversible blindness, which makes early diagnosis, with the goal of preserving vision, essential. The current medical intervention is to reduce intraocular pressure (IOP) to slow down progression of the disease. The main goal of this study was to test a novel handheld acoustic self-tonometer on humans.

Methods

A sound pressure pulse generated by a loudspeaker causes the eye to vibrate. A pressure chamber is placed on the human orbit to form a coupled system comprised of the patient's eye, the enclosed air, and the loudspeaker. A displacement sensor in front of the loudspeaker membrane allows the dynamic behavior of the entire system to be detected.

Results

For this clinical trial series, a prototype of the acoustic self-tonometer principle was applied. The resulting membrane oscillation data showed sensitivity of patient IOP, but direct allocation of the measured damping and frequency to the IOP was not significant. For this reason, an artificial neural network was used to find relationships among the subjects’ biometric eye parameters in combination with the self-tonometer data for the IOP reference. An expanded measurement uncertainty (k_p = 2) equal to 6.53 mm Hg was determined for the self-tonometer in a Bland–Altman analysis using Goldmann applanation tonometer reference measurements.

Conclusions

The usability and success rate of producing valid measurement values with the device during self-measurements by test subjects was nearly 92%. The cross-sensitivities observed require compensation in a possible redesign phase to reduce the measurement uncertainty by at least 25% to the maximum of 5 mm Hg required to seek medical device approval.

Translational Relevance

Building on successful laboratory experiments with pig eyes, this article reports the results of testing the acoustic tonometer on humans.

Initial experience in self-monitoring of intraocular pressure

Background/aims

Diurnal variation in intraocular pressure (IOP) is a routine assessment in glaucoma management. Providing patients the opportunity to perform self-tonometry might empower them and free hospital resource. We previously demonstrated that 74% of patients can use the Icare® HOME tonometer. This study further explores Icare® HOME patient self-monitoring.

Methods

Patients were trained by standard protocol to use the Icare® HOME rebound tonometer. Patient self-tonometry was compared to Goldmann applanation tonometry (GAT) over one clinical day. Following this, each patient was instructed to undertake further data collection that evening and over the subsequent two days.

Results

Eighteen patients (35 eyes) participated. Good agreement was demonstrated between GAT and Icare® HOME for IOPs up to 15 mm Hg. Above this IOP the Icare® tended to over-read, largely explained by 2 patients with corneal thickness >600 um. The mean peak IOP during ‘clinic hours’ phasing was 16.7 mm Hg and 18.5 mm Hg (p = 0.24) over three days. An average range of 5.0, 7.0 and 9.8 mm Hg was shown during single day clinic, single day home and three day home phasing respectively (p =<0.001). The range of IOP was lower in eyes with prior trabeculectomy (6.1 mm Hg vs 12.2 mm Hg). All patients undertook one reading in the early morning at home with an average of 4.8 readings during, and 3.1 readings after office hours.

Conclusions

This small study shows that self-tonometry is feasible. The findings from home phasing demonstrated higher peak and trough IOPs, providing additional clinical information. Home phasing is a viable alternative. The cost-effectiveness of this approach has yet to be addressed.

Determining Significant Elevation of Intraocular Pressure Using Self-tonometry

SIGNIFICANCE

Icare HOME rebound tonometry is increasingly adopted into clinical practice for IOP phasing of glaucoma patients and suspects. Because of measurement differences with applanation tonometry and diurnal fluctuations, interpretation of the IOP measured with Icare HOME phasing can be challenging.

PURPOSE

The purpose of this study was to use a large patient cohort to develop a practical, analytical tool for interpreting Icare HOME measurements with respect to applanation pressure.

METHODS

IOP measurements using the Icare HOME and an applanation tonometer were taken prospectively in 498 consecutive patients. Bland-Altman, frequency distribution, and linear regression analysis were applied to determine measurement differences. A novel criterion, Threshold Icare HOME IOP, was developed to assist identification of elevation above target applanation pressure, considering the expected diurnal variation and measurement variability.

RESULTS

Icare HOME tended to underestimate applanation tonometry (mean bias, -1.7 mmHg; 95% limits of agreement, -7.0 to +3.6). Overall, differences were within ±3 mmHg in 71.5% and ±5 mmHg in 92% of patients. Based on the novel criterion developed, Icare HOME measurements that exceed target applanation pressure by 6 mmHg or greater are generally outside the 95% limit of expected observations.

CONCLUSIONS

The Threshold Icare HOME IOP is a novel and practical criterion that can assist clinicians in their interpretation of Icare HOME phasing measurements with respect to target applanation pressures. Elevation above the expected thresholds may prompt closer monitoring or even modifications to glaucoma management.

Home monitoring for glaucoma

Glaucoma services are overwhelmed and struggling to accommodate current demand. Reducing the need for hospital based services would improve our ability to see those most at risk of vision loss, which could both reduce demand and improve patient outcomes. Digital technologies that provide opportunities for home monitoring of glaucoma progression have potential to contribute to solve these challenges and, potentially, improve glaucoma care. This article will review the literatures of well-established technologies that support home monitoring for glaucoma, specifically home tonometry (with rebound tonometry) and perimetry with Moorfields Motion Displacement Test and Melbourne Rapid Field.

Association Between 24-Hour Intraocular Pressure Monitored With Contact Lens Sensor and Visual Field Progression in Older Adults With Glaucoma

Importance

Twenty-four-hour intraocular pressure (IOP) patterns may provide more information regarding rates of visual field progression than office-hour measurements. However, little is known about the added value of 24-hour monitoring when stratifying glaucoma risk based on rates of progression.

Objective

To test the hypothesis that 24-hour IOP-related patterns recorded with a contact lens sensor (CLS) correlate with prior rates of visual field progression.

Design, Setting, and Participants

A multicenter, retrospective cohort study was conducted at 50 ophthalmology care centers in 13 countries. Participants included 445 patients (445 eyes) with treated, manifest open-angle glaucoma. The study was conducted from November 8, 1999, to September 17, 2016.

Interventions

Twenty-four-hour recordings of IOP-related patterns were prospectively collected with a CLS system. Retrospective visual field data of patients who underwent at least 3 prior reliable visual field tests were examined.

Main Outcomes and Measures

Association between CLS variables and rates of visual field mean deviation (MD) change.

Results

Of the 445 patients included, 238 (53.5%) were women and 394 (88.5%) were white. The mean (SD) age and MD values at the time of CLS recording were 68.9 (11.2) years and -9.0 (7.0) dB. The mean rate of MD change was -0.46 (0.5) dB/y in 5.2 (3) years of follow-up. After adjusting for baseline MD severity, age, and treatment, the following CLS variables were associated with fast visual field progression: mean peak ratio while awake (β = -0.021; 95% CI, -0.04 to -0.003), number of long peaks during sleep (β = 0.036; 95% CI, 0.005 to 0.067), night bursts ocular pulse frequency SD (β = 0.027; 95% CI, 0.004 to 0.051), and night bursts ocular pulse amplitude SD (β = 19.739; 95% CI, 1.333 to 38.145). Regression models including CLS variables had better fit than Goldmann IOP when testing the association with rates of progression.

Conclusions and Relevance

Results of this study indicate that 24-hour CLS recordings may be associated with prior rates of visual field progression of glaucoma. This association appears to be better than Goldmann mean IOP measured multiple times during office hours. Therefore, the CLS may be useful to assess the risk of future functional loss, even in situations when insufficient historical visual field information is available.

Self-monitoring of intraocular pressure using Icare HOME tonometry in clinical practice

Purpose: To determine the value of self-monitoring of diurnal intraocular pressure (IOP) by Icare Home rebound tonometer in patients with glaucoma and ocular hypertension.

Methods: Patients with open-angle glaucoma or ocular hypertension, controlled IOP at office visits, and at least 3 years of follow-up in the glaucoma clinic were included. Progression of glaucoma was based on medical records and defined by documented structural and/or visual field change. Patients were trained to correctly perform self-tonometry and instructed to measure diurnal IOP in a home setting for 3 days. IOP characteristics (mean, peak IOP, fluctuation of IOP as range, and SD of IOP) were documented and compared between the progressive and stable eyes.

Results: Ninety-four patients (50 females) with a mean (SD) age of 57.1 (14.7) years were included. Among the 94 eyes from 94 subjects, 72 (76.6%) eyes had primary open-angle glaucoma, ten (10.6%) had pigmentary glaucoma, four (4.3%) had exfoliative glaucoma, and eight (8.5%) eyes had ocular hypertension. Thirty-six eyes showed progression and 58 eyes were stable. Patients with progression were older than those with stable disease (mean (SD) 65.8 (8.4) years vs 51.7 (15.3) years, P<0.001). The progression group had higher average IOP (mean (SD) 15.8 (4.0) mmHg vs 13.3 (3.7) mmHg, P=0.002), peak IOP (mean (SD) 21.8 (5.8) mmHg vs 18.6 (4.8) mmHg, P=0.01), and greater IOP fluctuation range (mean (SD) 11.6 (4.8) vs 9.1 (3.5) mmHg, P=0.011) compared to non-progression group.

Conclusion: Self-monitoring of IOP using Icare Home tonometry provides more complete data on variability of IOP to assist in the management of glaucoma.

Self-measurement with Icare HOME tonometer, patients' feasibility and acceptability

PURPOSE

To evaluate and compare the accuracy of self-measurement of intraocular pressure using Icare Home rebound tonometer with Goldmann applanation tonometer and assess acceptability of self-tonometry in patients with glaucoma and ocular hypertension.

METHODS

In the study, 117 subjects were trained to use Icare Home for self-measurement. Icare Home tonometer readings were compared with Goldmann applanation tonometer, including one eye per patient. Agreement between the two methods of measurement was evaluated by Bland and Altmann analysis. Questionnaire was used to evaluate patients' perception of self-tonometry.

RESULTS

One hundred and three out of 117 patients (88%) were able to measure their own intraocular pressure and 96 (82%) fulfilled the requirements for certification. The mean (SD) difference Goldmann applanation tonometer minus Icare Home was 1.2 (2.4) mmHg (95% limits of agreement, -3.4 to 5.9 mmHg). The magnitude of bias between the two methods depended on central corneal thickness, with greater bias at central corneal thickness <500 µm. In 65 out of 96 subjects (67.7%), Icare Home results were within 2 mmHg of the Goldmann applanation tonometer. Seventy-three out of 93 (78.5%) felt that self-tonometry was easy to use and 75 patients (80.6%) responded that they would use the device at home.

CONCLUSION

Icare Home tonometry tends to slightly underestimate intraocular pressure compared to Goldmann applanation tonometer. Most patients were able to perform self-tonometry and found it acceptable for home use. Measurements using rebound self-tonometry could improve the quality of intraocular pressure data and optimize treatment regimen.

New Technologies for Glaucoma Detection

This review describes some of the most recent advances in the development and application of new technologies for detecting and managing glaucoma, including imaging, visual function testing, and tonometry. The widespread availability of mobile technology in the developing world is improving health care delivery, for example, with smartphones and mobile applications that allow patient data to be assessed remotely by health care providers.

21st century glaucoma care

Glaucoma care has evolved dramatically over the past generation, with changes that have incorporated new technology and improved understanding of the disease process. A major need is to construct a useful definition of glaucomatous optic neuropathy that can be used to compare data across clinical research studies. The treatment of glaucoma should now be based on achievement of a goal target for intraocular pressure, unique to each patient. Adherence with eye drop treatment is far from ideal and can be improved using reminder systems. Sustained delivery of glaucoma medication is on the horizon. New surgical approaches to glaucoma are being actively studied but have not as yet found their place in its care, with rigorous testing against present treatments needed.

Icare® rebound tonometers: review of their characteristics and ease of use

The rebound tonometer has a unique mechanism for measuring intraocular pressure (IOP) and has become popular worldwide due to its ease of use. The most notable advantages are the lack of an air-puff and need for topical anesthesia, ease of operation and transport, and the ability to use it with children. Four rebound tonometers (Icare® TA01i, Icare PRO, Icare HOME, and Icare ic100) are currently available for clinical examination. It is important to understand the characteristics of each tonometer and select the most appropriate one because the IOP values and the purpose of measurement are different. In this review, with the goal of improving the understanding of a range of tonometers, the issues with each device are discussed.

Twenty-four hour intraocular pressure measurements and home tonometry

PURPOSE OF REVIEW

IOP is the only treatable risk factor contributing to glaucoma and most management and treatment of glaucoma is based on IOP. However, current IOP measurements are limited to office hours and control of glaucoma in many patients would benefit from the ability to monitor IOP diurnally so as not to miss abnormal pressures, which occur outside of office hours Consequently, to improve patient care, the ability to enable accurate and minimally disruptive diurnal IOP monitoring would improve caring for these patients.

RECENT FINDINGS

The studies we selected for this review can be divided into three categories: self-/home-tonometry, continuous invasive intraocular pressure measurements, and continuous noninvasive ocular measurements.

SUMMARY

The desire to obtain better insight in our patients' true diurnal IOP has led to the development of home-tonometers, in addition to extraocular and intraocular continuous pressure measurement devices. All of the devices have respective advantages and disadvantages, but none to date completely fulfills the goal of providing a true diurnal IOP profile.Video abstracthttp://links.lww.com/COOP/A27.

Tonometers-which one should I use?

Although several factors are known to play a role in the development and progression of glaucoma, intraocular pressure (IOP) remains the only modifiable risk factor. Medical and surgical treatments for glaucoma both aim to reduce IOP to minimize disease progression. Tonometry is therefore an essential element of the ophthalmological exam. There are several types of tonometers available currently. These range from well-established instruments that have been in clinical use for decades to new devices, which are the result of recent technological advances. The various instruments have advantages and disadvantages that affect their suitability for a given setting, purpose, and patient population. In this review, we aim to describe the most commonly available tonometers today along with their advantages, disadvantages, and applicability.

Diurnal Intraocular Pressure Fluctuations with Self-tonometry in Glaucoma Patients and Suspects: A Clinical Trial

SIGNIFICANCE

This article shows that self-tonometry can provide robust measures of diurnal intraocular pressure (IOP) and also detect changes to IOP in response to treatment within a short period of monitoring. These advances in IOP monitoring may contribute to improved management of glaucoma patients and suspects.

PURPOSE

The aim of this study was to prospectively investigate the utility of rebound self-tonometry performed over several weeks for detecting diurnal IOP fluctuations in glaucoma patients and suspects and also initial response to topical treatment in glaucoma patients.

METHODS

Forty patients were recruited following glaucoma-specific examination. Subsequent to successful training with the iCare HOME tonometer, patients were instructed to measure IOP, in a sitting position, four times a day over 4 to 6 weeks. Date, time, laterality, and IOP downloaded from the tonometer and clinical examination data, including applanation IOP and corneal thickness, were analyzed. A user satisfaction survey was also administered at study completion. t Test and analysis of variance were used to compare groups and IOP across days. Pearson correlation was used to compare measurements to Goldmann applanation tonometry and IOP measurements from the first day/s to the overall mean IOP.

RESULTS

Twenty-seven patients (18 suspects and 9 glaucoma patients) completed data collection. Patients self-measured IOP on 118 (±29) occasions for 40 (±7.4) days. Two dominant patterns of fluctuation were revealed: peak IOP upon awakening (n = 11) and at midday (n = 13). Diurnal IOP measured in the first 7 days showed strong correlation to diurnal IOP across the entire study period (r = 0.82, P < .0001). Within 24 hours of treatment commencement (latanoprost 0.005% ophthalmic solution), IOP reduced from 23.9 (±5.2) to 16.1 (±2.6) mmHg. Overall, patients rated the instrument as easy to use, although difficulties with correct alignment were expressed.

CONCLUSIONS

Rebound self-tonometry demonstrated utility for measuring diurnal IOP fluctuations in most patients, hence enhancing management of patient with or at risk of developing glaucoma.

Measurement of Intraocular Pressure by Patients With Glaucoma

Importance

The ability of patients to measure their own intraocular pressure (IOP) would allow more frequent measurements and better appreciation of peak IOP and IOP fluctuation.

Objective

To examine whether patients with glaucoma can perform self-tonometry using a rebound tonometer and examine patient acceptability.

Design, Setting, and Participants

An observational study in which IOP was assessed using Goldmann applanation tonometry and a rebound tonometer. Consecutive patients were provided with a patient information sheet and those consenting to take part in the study received standardized self-tonometry training and were then instructed to measure their own IOP under observation. This study was conducted at a glaucoma clinic at a university hospital from March 1, 2016, to December 30, 2016, and included both eyes of 100 patients with glaucoma or ocular hypertension.

Main Outcomes and Measures

The percentage of patients who could successfully perform self-tonometry. Complete success was defined by a good technique and an IOP reading within 5 mm Hg of that obtained by a clinician using the same device. A 3-item questionnaire was used to examine perceptions of self-tonometry among patients.

Results

Among the 100 patients, the mean (SD) age was 67.5 (10.9) years (53% female). A total 73 of 100 patients (73%) met the complete success criteria. An additional 6 patients could use the device but had IOP readings greater than 5 mm Hg different from those obtained by the clinician. On average, IOP by the rebound tonometer was 2.66 mm Hg lower than Goldmann applanation tonometry (95% limits of agreement, -3.48 to 8.80 mm Hg). The IOPs with the rebound tonometer were similar whether obtained by self-tonometry or investigator, with excellent reproducibility with an intraclass correlation coefficient of 0.903 (95% CI, 0.867-0.928). A total of 56 of 79 successful or partially successful patients (71%) felt self-tonometry was easy, with 73 of 79 (92%) reporting self-tonometry to be comfortable, and a similar number happy to perform self-tonometry in the future.

Conclusions and Relevance

Most patients could perform self-tonometry and the method was acceptable to patients. Self-tonometry has the potential to improve patient engagement, while also providing a more complete picture of IOP changes over time.

Critical pathway for primary open angle glaucoma diagnosis

AIM

To develop a critical pathway for primary open angle glaucoma (POAG) diagnosis intended to be efficient, to unify criteria, reduce resource use and minimize costs to the health system.

METHODS

We performed a systematic search on PubMed, Cochrane, Embase and ClinicalTrials.org databases and classified the quality of evidence from level I through III.

RESULTS

A critical pathway was designed by setting a key-decision step by step model on the basis of the best current evidence.

CONCLUSION

A critical pathway, evidence-based guideline, may be a useful tool intended to reduce costs while maintaining or even improving the quality of care for diagnosing a highly prevalent pathology such as open angle glaucoma.