Visual Function Measurements from the nGoggle are Associated with Patient-Reported Quality of Life in Glaucoma

Abstract

Purpose : The nGoggle (nGoggle, Inc., San Diego, CA) is a portable brain-computer interface designed to objectively assess functional loss in glaucoma and other eye diseases. A previous study has shown that nGoggle measurements are associated with visual field loss detected by standard automated perimetry (SAP). This study aimed at investigating whether functional loss measured by the nGoggle is also associated with patient-reported quality of life outcomes, as assessed by the National Eye Institute Visual Function Questionnaire (NEI VFQ-25).

Methods : 37 glaucoma patients and 14 healthy individuals were included in the study. All subjects were tested by the nGoggle, SAP SITA 24-2 and also responded NEI VFQ-25 questionnaires. The nGoggle is a portable device that integrates wearable, wireless, dry electroencephalogram and electrooculogram systems, and a head-mounted display (HMD), allowing detection of multifocal steady-state visual evoked potentials (mfSSVEP) associated with visual field stimulation (Figure 1). Rasch analysis was performed to obtain final scores of disability as measured by the NEI VFQ-25. Linear regression models were used to investigate the association between NEI VFQ-25 Rasch-calibrated scores and the global nGoggle mfSSVEP parameter, as well as SAP Mean Deviation (MD). Analyses were performed for the better and worse eyes for both nGoggle and SAP.

Results : Patients with glaucoma had significantly worse nGoggle mfSSVEP measurements compared to healthy subjects (0.300 +- 0.233 vs. 0.342 +- 0.022, respectively; P<0.001). There was a statistically significant relationship between nGoggle measurements in the better eye and NEI VFQ-25 scores (r=0.352; P=0.011). Similar results were found for the worse eye. SAP MD in the better eye had a similar correlation to NEI VFQ-25 scores (r=0.347; P=0.013). In a multivariable model adjusting for age, gender, and race, nGoggle mfSSVEP measurements were still significantly associated with NEI VFQ-25 scores (P=0.010).

Conclusions : Assessment of neural damage by the nGoggle was significantly associated with patient-reported quality of life outcomes as measured by the NEI VFQ-25. This finding indicates that nGoggle measurements are indicative of patient disability and may be useful biomarkers for functional loss in glaucoma.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.