Eye metrics are a marker of visual conscious awareness and neural processing in cerebral blindness

Abstract

Damage to the primary visual pathway can cause vision loss. Some cerebrally blind people retain degraded vision or sensations and can perform visually guided behaviors. These cases motivate investigation and debate on blind field conscious awareness and linked residual neural processing. A key challenge in this research is that subjective measures of blind field visual conscious awareness can be misleading. Alternatively, eye metrics, including pupil size and eye movements are promising objective markers of conscious awareness and brain activity. In this study, we examined stimulus-evoked changes in pupil size, blinking, and microsaccades in the sighted and blind field of cerebrally blind participants. Using standard analysis and innovative machine learning methods, our findings support that eye metrics can infer blind field conscious awareness, even when behavioral performance on a visual perception task indicated otherwise. Furthermore, these eye metrics were linked to blind field visual stimulus-evoked occipital cortical field potentials. These findings support recording eye metrics in cerebral blindness and highlight potential clinical applications, including tracking the recovery of conscious vision and visual neural processing.