The nGoggle: A portable brain-based device for assessment of visual function deficits

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PROJECT SUMMARY Assessment of visual function loss outside the foveal area is an essential component of the management of numerous conditions, including glaucoma, retinal and neurological disorders. Despite the significant progress achieved with the development of standard automated perimetry (SAP) many decades ago, assessment of visual field loss with SAP still has significant drawbacks. SAP testing is limited by subjectivity of patient responses and high test-retest variability, frequently requiring many tests for effective detection of change over time. Moreover, as these tests are generally conducted in clinic-based settings, limited patient availability and health care resources often result in an insufficient number of tests acquired over time, with delayed diagnosis and detection of disease progression. The requirement for highly trained technicians, cost, complexity, and lack of portability of SAP also preclude its use for screening of visual field loss in underserved populations. To address shortcomings of current methods to assess visual function, we have developed the nGoggle, a wearable device that uses a head-mounted display (HMD) integrated with wireless electroencephalography (EEG), capable of objectively assessing visual field deficits using multifocal steady-state visual-evoked potentials (mfSSVEP). In our NEI SBIR Phase I project, we developed the nGoggle prototype using a modified smartphone-based HMD display and non-disposable electrodes. We also conducted benchmarking tests on signal quality of EEG acquisition, developed methods for EEG data extraction and analysis, and conducted a pilot study demonstrating the ability of the device to detect visual field loss in glaucoma. Based on the encouraging results from Phase I and a clear delineation of the steps needed to bring the device into a final commercial product, we proceeded to conduct the NEI STTR Phase II studies with the specific aims: 1) to develop a customized head-mounted display and enhanced no-prep electrodes for improving nGoggle’s ability to acquire users’ mfSSVEP with high signal- to-noise ratios (SNR) in response to visual stimulation; 2) to optimize and validate mfSSVEP stimuli design and data analytics to enhance the accuracy and repeatability of assessing visual function loss with the nGoggle; 3) to complete pivotal clinical studies to support FDA approval. Due to the lack of progress in expanding their field of view (FOV) among the commercially available head-mounted near-eye displays using reflective optical wave- guides (ROW), we need to develop a customized near eye display (NED) with the required FOV of 60° diagonal using a micro-AMOLED panel and a Free Form Surface (FFS) reflector. This Administrative Supplement for Research will provide the necessary funding for a six-month sub-project to develop the customized near eye display and the software image compensation against the optical distortion in the expanded field of view. The technology will then be used to achieve the specific aims of our Phase II project and get the nGoggle ready for commercial production.