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

Reliability of Visual Field Testing in a Telehealth Setting Using a Head-Mounted Device: A Pilot Study

PRCIS

Monitoring visual fields (VFs) through virtual reality devices proved to have good inter-test and test-retest reliability, as well as easy usability, when self-administered by individuals with and without VF defects in a remote setting.

PURPOSE

To assess the reliability of remote, self-administered VF monitoring using a virtual reality VF (VRVF) device in individuals without ocular disease and with stable VF defects.

MATERIALS AND METHODS

Individuals without ocular disease and with stable defects were recruited. All participants had a baseline standard automated perimetry (SAP) test. Participants tested remotely on a VRVF device for 4 weeks (examinations V 1 , V 2 , V 3 , and V 4 ), with the last 3 unassisted. The mean sensitivities of VRVF results were compared with each other and to SAP results for reliability.

RESULTS

A total of 42 eyes from 21 participants were tested on the VRVF device. Participants tested consistently although external factors impacted outcomes. VRVF results were in reasonable agreement with the baseline SAP. Examinations performed by the cohort with stable defects evinced better agreement with SAP examinations (V2, P = 0.79; V3, P = 0.39; V4, P = 0.35) than those reported by the cohort without ocular disease (V2, P = 0.02; V3, P = 0.15; V4, P = 0.22), where the null hypothesis is that the instruments agree. Fixation losses were high and variable in VRVF examinations compared with those of SAP, particularly in certain test takers. Participants considered the device comfortable and easy to use.

CONCLUSIONS

Self-administered, remote VF tests on a VRVF device showed satisfactory test-retest reliability, good inter-test agreement with SAP, and acceptability by its users. External factors may impact at-home testing and age and visual impairment may hinder fixation. Future studies to expand the sample size and understand inconsistencies in fixation losses are recommended.

Performance of a Smart Device over 12-Months for Home Monitoring of Patients with Intermediate Age-Related Macular Degeneration

Background: To determine the 12-month compliance with and retention of home monitoring (HM) with Melbourne Rapid Fields (MRFh) for patients with intermediate age-related macular degeneration (iAMD) and compare visual acuity (VA) and retinal sensitivity (RS) results to clinical measures. Methods: Participants were recruited to a 12-month HM study with weekly testing of vision with MRFh. Inclusion criteria were a diagnosis of iAMD, understand English instructions, VA ≥ 20/40, and access to an iPad. Supervised in-clinic testing of high contrast VA (HVA, ETDRS), low-luminance VA (LLVA, ETDRS with ND2 filter), and RS (Macular Integrity Assessment, MAIA, and MRF in-clinic, MRFc) was conducted every 6-months. Results: A total of 54 participants (67 ± 6.8 years) were enrolled. Compliance to weekly HM was 61% and study retention at 12-months was 50% of those with uptake (n = 46). No difference was observed between MRFc and MRFh across all RS and VA outcomes (p > 0.05). MRFh RS was higher than MAIA (29.1 vs. 27.1 dB, p < 0.001). MRFh HVA was not different from ETDRS (p = 0.08), but LLVA was 9 letters better (81.5 vs. 72.4 letters, p < 0.001). Conclusions: Over 12-months, MRFh yields a moderate level of compliance with (61%) and retention (50%) of weekly testing. Further studies are required to assess the ability of MRFh to detect early progression to nAMD.

Deep Learning-Based Glaucoma Screening Using Regional RNFL Thickness in Fundus Photography

Since glaucoma is a progressive and irreversible optic neuropathy, accurate screening and/or early diagnosis is critical in preventing permanent vision loss. Recently, optical coherence tomography (OCT) has become an accurate diagnostic tool to observe and extract the thickness of the retinal nerve fiber layer (RNFL), which closely reflects the nerve damage caused by glaucoma. However, OCT is less accessible than fundus photography due to higher cost and expertise required for operation. Though widely used, fundus photography is effective for early glaucoma detection only when used by experts with extensive training. Here, we introduce a deep learning-based approach to predict the RNFL thickness around optic disc regions in fundus photography for glaucoma screening. The proposed deep learning model is based on a convolutional neural network (CNN) and utilizes images taken with fundus photography and with RNFL thickness measured with OCT for model training and validation. Using a dataset acquired from normal tension glaucoma (NTG) patients, the trained model can estimate RNFL thicknesses in 12 optic disc regions from fundus photos. Using intuitive thickness labels to identify localized damage of the optic nerve head and then estimating regional RNFL thicknesses from fundus images, we determine that screening for glaucoma could achieve 92% sensitivity and 86.9% specificity. Receiver operating characteristic (ROC) analysis results for specificity of 80% demonstrate that use of the localized mean over superior and inferior regions reaches 90.7% sensitivity, whereas 71.2% sensitivity is reached using the global RNFL thicknesses for specificity at 80%. This demonstrates that the new approach of using regional RNFL thicknesses in fundus images holds good promise as a potential screening technique for early stage of glaucoma.

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.