An Open-source Static Threshold Perimetry Test Using Remote Eye-tracking (Eyecatcher): Description, Validation, and Preliminary Normative Data

Glaucoma Home Self-Testing Using VR Visual Fields and Rebound Tonometry Versus In-Clinic Perimetry and Goldmann Applanation Tonometry: A Pilot Study

Purpose

This pilot study aimed to assess the feasibility, accuracy, and repeatability of unsupervised, at-home, multi-day glaucoma testing using the Olleyes VisuALL Virtual Reality Platform (VRP) and the iCare HOME handheld self-tonometer.

Methods

Participants were trained to use two U.S. Food and Drug Administration-registered or approved devices before conducting self-tests at home over 3 consecutive days. The iCare HOME intraocular pressure (IOP) measurements were collected four times daily per eye, and VRP visual field tests were performed once daily. The results were compared with one in-clinic Humphrey Field Analyzer (HFA) visual field test performed on the day of device training, iCare HOME measurements by the trainer, and the last five Goldmann applanation tonometer (GAT) results.

Results

Of 15 enrolled participants, nine of them (60%) completed the study. The six excluded participants could not self-measure using iCare HOME. There was significant correlation between the average mean deviation (MD) values of the at-home VRP tests and in-clinic HFA test (r2 = 0.8793, P < 0.001). Additionally, the average of the sensitivities in five of six Garway-Heath sectors were significantly correlated. VRP test duration was also shorter than in-clinic HFA testing (P < 0.001). Finally, at-home tonometry yielded statistically similar values compared to trainer-obtained iCare HOME values. The mean and range of at-home tonometry were also statistically similar to those for in-clinic GAT, but at-home tonometry demonstrated higher maximum IOP values (P = 0.0429).

Conclusions

Unsupervised, at-home, multi-day glaucoma testing using two devices resulted in the capture of higher maximum IOPs than in the clinic and good MD correlation of VRP with HFA. However, 40% of participants could not self-measure IOP using iCare HOME.

Translational Relevance

The study findings suggest that at-home remote glaucoma monitoring correlates with in-office testing and could provide additional information for glaucoma management, although patients had more difficulty with the iCare HOME than the VRP.

Portable devices for diagnosis and monitoring of glaucoma: a scoping review protocol

INTRODUCTION

Glaucoma is the leading cause of irreversible blindness in the world. The need to diagnose glaucoma early in its natural history before extensive sight loss occurs cannot be overemphasised. However, glaucoma is largely asymptomatic in the early stages of the disease making it complex to diagnose clinically and requires the support of technology. The objective of this scoping review is to determine the nature and extent of the evidence for use of portable devices in the diagnosis of glaucoma.

METHODS

We will consider studies conducted in all healthcare settings using portable devices for the detection of all type of adult glaucoma. We will also include any systematic reviews or scoping reviews, which relate to this topic. Searches will be conducted in MEDLINE, Embase, CENTRAL on the Cochrane Library and Global Health databases, from their inception to the present. Reference lists from publications identified in the searches will also be reviewed. Two authors will independently screen titles and abstracts, followed by full-text screening to assess studies for inclusion. Any disagreements will be discussed and resolved with a third author. Tables accompanied by narrative descriptions will be employed to discuss results and show how it relates to review questions.

ETHICS AND DISSEMINATION

Ethical approval is not required in this review. Only published and publicly accessible data will be used. We will publish our findings in an open-access, peer-reviewed journal and develop an accessible summary of results and recommendations.

Descriptive study of the challenges when implementing an app for patients with neovascular age-related macular degeneration to monitor their vision at home

OBJECTIVES

Remote monitoring of health has the potential to reduce the burden to patients of face-to-face appointments and make healthcare more efficient. Apps are available for patients to self-monitor vision at home, for example, to detect reactivation of age-related macular degeneration (AMD). Describing the challenges when implementing apps for self-monitoring of vision at home was an objective of the MONARCH study to evaluate two vision-monitoring apps on an iPod Touch (Multibit and MyVisionTrack).

DESIGN

Diagnostic Test Accuracy study.

SETTING

Six UK hospitals.

METHODS

The study provides an example of the real-world implementation of such apps across health sectors in an older population. Challenges described include the following: (1) frequency and reason for incoming calls made to a helpline and outgoing calls made to participants; (2) frequency and duration of events responsible for the tests being unavailable; and (3) other technical and logistical challenges.

RESULTS

Patients (n=297) in the study were familiar with technology; 252/296 (85%) had internet at home and 197/296 (67%) had used a smartphone. Nevertheless, 141 (46%) called the study helpline, more often than anticipated. Of 435 reasons for calling, all but 42 (10%) related to testing with the apps or hardware, which contributed to reduced adherence. The team made at least one call to 133 patients (44%) to investigate why data had not been transmitted. Multibit and MyVisionTrack apps were unavailable for 15 and 30 of 1318 testing days for reasons which were the responsibility of the app providers. Researchers also experienced technical challenges with a multiple device management system. Logistical challenges included regulations for transporting lithium-ion batteries and malfunctioning chargers.

CONCLUSIONS

Implementation of similar technologies should incorporate a well-resourced helpline and build in additional training time for participants and troubleshooting time for staff. There should also be robust evidence that chosen technologies are fit for the intended purpose.

TRIAL REGISTRATION NUMBER

ISRCTN79058224.

Development and Validation of an Internet-Based Remote Perimeter (Perimouse)

Purpose

We sought to validate the feasibility of Perimouse, an internet-based remote perimeter that allows for natural fixation and can be performed on most computers via a web page.

Methods

In this cross-sectional study, Perimouse evaluated the visual field of 45 healthy people and 27 patients with primary open-angle glaucoma on a laptop. Participants used a mouse cursor to locate new dots on the screen that were determined by preset saccade vectors. A "click and confirm" strategy was used to eliminate the unwanted visual search. Dot brightness was either fixed at 12 dB in the suprathreshold program (screening program) or variable in the threshold program. We compared Perimouse outcomes with the Humphrey Field Analyzer (HFA) 24-2 Swedish Interactive Testing Algorithm standard program.

Results

In the screening program, Perimouse showed moderate to high concordance with HFA. The intraclass coefficient ranged from 0.58 to 0.86 in different areas of Garway-Heath mapping. In the threshold program, normal subjects had threshold ranging from 19 to 16 dB, presenting sensitivity changes according to the "hill of vision". The test-retest difference was 0.09 dB. Habitual spectacle correction and environmental luminance (2-337 lux) had little impact on the central or peripheral threshold (P > 0.05). The correlation between Perimouse and HFA threshold sensitivity was strong (R = 0.950), although Perimouse mean defect was 4.40 dB higher than the HFA mean defect.

Conclusions

Perimouse is a reliable visual field test that correlates strongly with HFA. It shows potential for population screening and monitoring visual field defects.

Translational Relevance

Perimouse assesses the visual field using saccade vectors without eye trackers, enhancing its accessibility via a web page.

Online Circular Contrast Perimetry via a Web-Application: Establishing a Normative Database for Central 10-Degree Perimetry

Purpose

To establish a normative database using a central 10-degree grid pattern for the online circular contrast perimetry (OCCP) application.

Participants

Fifty participants with mean age 65 ± 13 years were selected for this study. One eye from each participant that met inclusion criteria was randomly included in the cohort.

Methods

The web-application delivered online 52-loci perimetry in a central 10-degree pattern using circular flickering targets. These targets consist of concentric sinusoidal alternating contrast rings. Users were guided by the application to the correct viewing distance and head position using in-built blind spot localization and webcam monitoring. A spinning golden star was used as the fixation target and patients performed the test in a darkened room following standard automated perimetry (SAP).

Results

The reliability rates and global indices for OCCP were similar to SAP. OCCP mean sensitivity reduced with age at a similar rate to SAP. Mean sensitivity per loci of 10-degree OCCP was greater than SAP by 1.24 log units (95% CI 1.23 to 1.26) and obeyed a physiological hill of vision. Small differences existed in mean sensitivities between OCCP and SAP which increased with increasing spot eccentricity. Mean deviation (MD) displayed good agreement between the two tests.

Conclusion

Central 10-degree online circular contrast perimetry via a computer-based application has comparable perimetric results to standard automated perimetry in a normal cohort.

A review of experimental task design in psychophysical eye tracking research

While eye tracking is a technique commonly used in the experimental study of higher-level perceptual processes such as visual search, working memory, reading, and scene exploration, its use for the quantification of basic visual functions (visual acuity, contrast sensitivity, color vision, motion detection) is less explored. The use of eye movement features as dependent variables in a psychophysical investigation can serve multiple roles. They can be central in studies with neurological patients or infants that cannot comply with verbal instructions, understand task demands, and/or emit manual responses. The technique may also serve a complementary role, determining the conditions under which a manual or verbal response is given, such as stimulus position in the visual field, or it can afford the analysis of new dependent variables, such as the time interval between oculomotor and manual responses. Our objective is to review the literature that applied the eye tracking technique to psychophysical problems. The two questions our review raises are: can eye movements (reflex or voluntary) be an objective index of stimulus detection in psychophysical tasks? If so, under what conditions, and how does it compare with traditional paradigms requiring manual responses? Our (non-systematic) methodological review selected studies that used video-oculography as the technique of choice and had a basic visual function as their primary object of investigation. Studies satisfying those criteria were then categorized into four broad classes reflecting their main research interest: (1) stimulus detection and threshold estimation, (2) the effects of stimulus properties on fixational eye movements, (3) the effects of eye movements on perception, and (4) visual field assessment. The reviewed studies support the idea that eye tracking is a valuable technique for the study of basic perceptual processes. We discuss methodological characteristics within each of the proposed classification area, with the objective of informing future task design.

Eye Tracking in Optometry: A Systematic Review

This systematic review examines the use of eye-tracking devices in optometry, describing their main characteristics, areas of application and metrics used. Using the PRISMA method, a systematic search was performed of three databases. The search strategy identified 141 reports relevant to this topic, indicating the exponential growth over the past ten years of the use of eye trackers in optometry. Eye-tracking technology was applied in at least 12 areas of the field of optometry and rehabilitation, the main ones being optometric device technology, and the assessment, treatment, and analysis of ocular disorders. The main devices reported on were infrared light-based and had an image capture frequency of 60 Hz to 2000 Hz. The main metrics mentioned were fixations, saccadic movements, smooth pursuit, microsaccades, and pupil variables. Study quality was sometimes limited in that incomplete information was provided regarding the devices used, the study design, the methods used, participants' visual function and statistical treatment of data. While there is still a need for more research in this area, eye-tracking devices should be more actively incorporated as a useful tool with both clinical and research applications. This review highlights the robustness this technology offers to obtain objective information about a person's vision in terms of optometry and visual function, with implications for improving visual health services and our understanding of the vision process.

Comparison of Visual Field Test Measurements With a Novel Approach on a Wearable Headset to Standard Automated Perimetry

PRCIS

This study of inter-test comparability of a novel visual field application installed on an augmented-reality portable headset and Humphrey field analyzer Swedish interactive thresholding algorithm (SITA) Standard visual field test demonstrates the excellent correlation of mean deviation (MD) and mean sensitivity (MS).

PURPOSE

To determine the correlation between visual field testing with novel software on a wearable headset versus standard automated perimetry.

PATIENTS AND METHODS

Patients with and without visual field defects attributable to glaucoma had visual field testing in one eye of each patient with 2 methods: re:Imagine Strategy (Heru, Inc.) and the Humphrey field analyzer (Carl Zeiss Meditec, Inc.) SITA Standard 24-2 program. Main outcome measures included MS and MD, which were evaluated by linear regression, intraclass correlation coefficient (ICC), and Bland Altman analysis for assessment of the mean difference and limits of agreement.

RESULTS

Measurements from 89 eyes of 89 patients (18 normal and 71 glaucomas) were compared with both instruments. Linear regression analysis demonstrated an excellent Pearson correlation coefficient of r = 0.94 for MS and r = 0.95 for MD. ICC analysis demonstrated high levels of concordance (ICC = 0.95, P < 0.001 for MS and ICC = 0.94, P < 0.001 for MD). Bland-Altman analysis determined a small mean difference between the two devices (Heru minus Humphrey) of 1.15 dB for MS and 1.06 dB for MD.

CONCLUSIONS

The Heru visual field test correlated well with SITA Standard in a population of normal eyes and eyes with glaucoma.

Test Reliability and Compliance to a Twelve-Month Visual Field Telemedicine Study in Glaucoma Patients

Background: Our primary aim is to quantify test reliability and compliance of glaucoma patients to a weekly visual field telemedicine (VFTM) schedule. A secondary aim is to determine concordance of the VFTM results to in-clinic outcomes. Methods: Participants with stable glaucoma in one eye were recruited for a 12 month VFTM trial using the Melbourne Rapid Fields (MRF-home, MRFh) iPad application. Participants attended routine 6 month clinical reviews and were tasked with weekly home monitoring with the MRFh over this period. We determined compliance to weekly VFTM (7 + 1 days) and test reliability (false positives (FPs) and fixation loss (FL) <33%). A secondary aim considered concordance to in-clinic measures of visual field (MRF-clinic (MRFc) and the Humphrey Field Analyzer (HFA)) in active participants (≥10 home examinations and 5 reliable HFA examinations). The linear trend in the MRFh mean deviation (MD) was compared to the HFA guided progression analysis (GPA) using Bland−Altman methods. Data are shown as the mean ± standard deviation. Results: Forty-seven participants with a mean age of 64 ± 14.6 years were recruited for the trial. The VFTM uptake was 85% and compliance to weekly home monitoring was 75% in the presence of weekly text reminders in the analysed group (n = 20). The analysed group was composed of test subjects with five reliable in-clinic HFA examinations (GPA analysis available) and who submitted a minimum of 10 MRFh examinations from home. Of the 757 home examinations returned, approximately two-thirds were reliable, which was significantly lower than the test reliability of the HFA in-clinic (MRFh: 65% vs. HFA: 85%, p < 0.001). The HFA-GPA analysis gave little bias from the MRFh slope (bias: 0.05 dB/yr, p > 0.05). Two eyes were found to have clinical progression during the 12 month period, and both were detected by VFTM. Conclusions: VFTM over 12 months returned good compliance (75%) to weekly testing with good concordance to in-clinic assays. VFTM is a viable option for monitoring patients with glaucoma for visual field progression in between clinical visits.

Spotlight on iPad Visual Field Tests Efficacy

Tablet based perimetry has the potential to be used as a low-cost, portable method for glaucoma screening. With the advent of tablets with large dynamic luminance range and high spatial resolution, perimetry applications can test visual field locations within the central 30 degrees, just like bowl perimetry. Tablet perimetry has garnered interest in this COVID era as it can be promptly done in the waiting room or even from the comfort of home. The current review focuses on evaluating glaucoma detection sensitivities, diagnostic abilities and correlation of each parameter and examination time of the iPad based perimetry applications with those of HFA.

The Open Perimetry Initiative: A framework for cross-platform development for the new generation of portable perimeters

The Open Perimetry Initiative was formed in 2010 with the aim of reducing barriers to clinical research with visual fields and perimetry. Our two principal tools are the Open Perimetry Interface (OPI) and the visualFields package with analytical tools. Both are fully open source. The OPI package contains a growing number of drivers for commercially available perimeters, head-mounted devices, and virtual reality headsets. The visualFields package contains tools for the analysis and visualization of visual field data, including methods to compute deviation values and probability maps. We introduce a new frontend, the opiApp, that provides tools for customization for visual field testing and can be used as a frontend to run the OPI. The app can be used on the Octopus 900 (Haag-Streit), the Compass (iCare), the AP 7000 (Kowa), and the IMO (CREWT) perimeters, with permission from the device manufacturers. The app can also be used on Android phones with virtual reality headsets via a new driver interface, the PhoneHMD, implemented on the OPI. The use of the tools provided by the OPI library is showcased with a custom static automated perimetry test for the full visual field (up to 50 degrees nasally and 80 degrees temporally) developed with the OPI driver for the Octopus 900 and using visualFields for statistical analysis. With more than 60 citations in clinical and translational science journals, this initiative has contributed significantly to expand research in perimetry. The continued support of researchers, clinicians, and industry are key in transforming perimetry research into an open science.

Glaucoma Screening Using an iPad-Based Visual Field Test in a West African Population

PURPOSE

To investigate the performance of the Melbourne Rapid Fields (MRF) for use in clinic-based visual field testing in a low-resource setting.

DESIGN

Prospective cross-sectional study.

PARTICIPANTS

One hundred and three participants (66 patients with glaucoma and 37 control participants) attending a clinical appointment at the Tema Eye Center, Tema, Ghana.

METHODS

Patients with glaucoma and control participants underwent MRF and Humphrey Field Analyzer (HFA) testing.

MAIN OUTCOME MEASURES

Mean deviation (MD), pattern standard deviation (PSD), reliability parameters, sensitivity, specificity, and area under the receiver operating characteristic curve.

RESULTS

Mean MD was less negative and mean PSD was more positive on the MRF than the HFA in both groups (all P < 0.001). False-positive and false-negative rates were comparable between methods (P = 0.09 and P = 0.35, respectively). In patients with glaucoma, MD and PSD from the 2 devices were correlated strongly (r = 0.84; P < 0.001) and moderately (r = 0.61; P < 0.001), respectively. Agreement analysis revealed that MRF tended to generate significantly higher MD (bias, 3.3 ± 4.1 dB; P = 0.03) and PSD (bias, 1.9 ± 2.8 dB; P = 0.03) with wide limits of agreement. For detecting moderate to advanced glaucoma, the sensitivity was 60.9% for the MRF and 78.3% for the HFA (P = 0.10); respective specificities were 86.5% and 83.8% (P = 0.76).

CONCLUSIONS

The MRF underestimated MD and overestimated PSD values compared with the HFA. Agreement biases were significant, suggesting a weak agreement between the 2 devices. However, the MRF showed potential for screening in a low-resource setting, particularly for detecting moderate to advanced glaucoma.

Eye-Movement-Based Assessment of the Perceptual Consequences of Glaucomatous and Neuro-Ophthalmological Visual Field Defects

Purpose

Assessing the presence of visual field defects (VFD) through procedures such as perimetry is an essential aspect of the management and diagnosis of ocular disorders. However, even the latest perimetric methods have shortcomings-a high cognitive demand and requiring prolonged stable fixation and feedback through a button response. Consequently, an approach using eye movements (EM)-as a natural response-has been proposed as an alternate way to evaluate the presence of VFD. This approach has given good results for computer-simulated VFD. However, its use in patients is not well documented yet. Here we use this new approach to quantify the spatiotemporal properties (STP) of EM of various patients suffering from glaucoma and neuro-ophthalmological VFD and controls.

Methods

In total, 15 glaucoma patients, 37 patients with a neuro-ophthalmological disorder, and 21 controls performed a visual tracking task while their EM were being recorded. Subsequently, the STP of EM were quantified using a cross-correlogram analysis. Decision trees were used to identify the relevant STP and classify the populations.

Results

We achieved a classification accuracy of 94.5% (TPR/sensitivity = 96%, TNR/specificity = 90%) between patients and controls. Individually, the algorithm achieved an accuracy of 86.3% (TPR for neuro-ophthalmology [97%], glaucoma [60%], and controls [86%]). The STP of EM were highly similar across two different control cohorts.

Conclusions

In an ocular tracking task, patients with VFD due to different underlying pathology make EM with distinctive STP. These properties are interpretable based on different clinical characteristics of patients and can be used for patient classification.

Translational Relevance

Our EM-based screening tool may complement existing perimetric techniques in clinical practice.

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.