Bridging the gap between visual function and functional vision
Functional vision refers to people’s vision-related abilities and determines whether they can drive, read, cook, walk, take the stairs, or exchange glances with a partner. While functional vision is clearly statistically related to visual function—objective measurements of the eye made by an ophthalmologist or optometrist—patients with vision loss who have similar visual function can vary widely in their functional vision. The aim of this research programme, funded by an NWO VIDI grant, is to establish what factors influence these individual differences. Specifically, we test the hypothesis that individual differences in functional vision can be explained by idiosyncratic neural factors. Broadly speaking, there are two ways in which the brain responds to vision loss: neural compensation and neural degeneration. Compensation may lead to better functional vision, while degeneration may worsen it. Individual differences in compensation and degeneration may explain individual differences in functional vision, despite similar levels of visual function.
The effects of neural compensation and degeneration can be measured with magnetic resonance imaging (MRI). The challenge is to quantify these effects at the individual level. We overcome this challenge by (1) modelling the normal levels of variation of the structure and function of the human visual brain based on MRI data of tens of thousands of individuals, (2) use these normative models to quantify neural deviations in individuals with eye disease, and (3) test the extent to which these deviations explain functional vision over and above visual function. This requires a fundamentally new approach of studying the human visual brain, capitalising on state-of-the-art data-analytic measures developed in our lab, and on the latest advances in big-data neuroimaging. Beyond improving scientific understanding, the outcomes provide critical insight into the functional consequences of vision loss—which ultimately matters most to the patient—and help setting realistic expectations about the latitude for rehabilitation.
Lifelong Vision
Blindness is rated among the top 15 causes of disability. The Lifelong Vision project aims to develop groundbreaking new treatments for blindness by repairing faulty genes, printing new retinas with a bio-printer, investigating how zebrafish manage to repair their own retinas, and by developing artificial intelligence to determine who is eligible for which treatment. The resulting technologies and treatments will serve as a blueprint for other diseases and organs. The consortium led by Radboud University Medical Centre has received 22 million euros for this purpose from the NWO Gravitation program of the Ministry of Education, Culture and Science.
The treatments that will be developed in this project aim to restore visual signals in the eye, but the brain must also be able to process these signals. Our role in this project is to develop new, brain scan-based indicators that can be used to monitor the effectiveness of the treatments. Furthermore, we want to identify individuals who are likely to benefit from these treatments in daily life. These indicators are not only necessary to apply the new treatments in clinical practice but also as outcome measures in clinical studies.
VR4eVR: Virtual Reality for enriched Visual Rehabilitation
Stroke-related damage to the central neural pathways from the eye to the brain results in partial blindness. Affected individuals often become blind in one half of their visual field. Although not fully blind, this impairment severely impacts their physical, social, and emotional wellbeing, and limits their ability to maintain a healthy lifestyle and participate in society. Our aim is to understand how to make vision training more accessible and effective, and how this translates into healthier living.
With VR4eVR, we will create an enriched, adaptive, at-home vision training system that deploys virtual reality (VR) technology, serious gaming elements, and on-line monitoring. We will optimize training effectiveness for individuals based on neuroscientifically-motivated personal biomarkers. Additionally, the VR will demonstrate to family, employers, and caregivers, in simulation, the consequences of the visual impairment. These solutions will be evaluated in field labs at regional rehabilitation centers that serve groups of different socio-economic statuses (SES), which allows optimizing them.
VR4eVR is funded by an NWO KIC grant and brings together individuals with stroke-induced vision impairment and professionals from private, public and academic partners to transform vision rehabilitation following stroke. This transformation will remove barriers and alleviate pressure on health care by optimizing both accessibility and effectiveness via at-home rehabilitation.