In plain sight: From clinical observations to a systematic assessment of visual behaviour for children with Cerebral Visual Impairment

Cerebral Visual Impairment (CVI) is a visual disorder that is caused by damage to or maldevelopment of the brain. It is the most common visual impairment in children. Within their heterogeneous and complex visual profile, visual selective attention (VSA) deficits are common. Current clinical diagnostic CVI assessments have several challenges: (1) Existing assessment tools focus on performance measures, which limits our understanding of the atypical daily visual behaviour of children with CVI; (2) Differentiating CVI from ADHD and dyslexia is challenging due to overlapping symptoms; (3) Existing assessment tools are not appropriate for preschool children with CVI as they rely on verbal instructions and require verbal or fine motor skills from the child. Consequently, CVI is often diagnosed after the age of 6.

This thesis set out to address these key challenges. We adapted existing CVI questionnaires and search tasks, and developed new screening lists and eye tracking-based search tasks. Overall, the thesis aimed to better understand the visual behaviour of children with CVI and improve the diagnostic CVI assessments.

We demonstrated that children with CVI show unique and atypical visual behaviour, characterized by a lack of overview and by overlooking visual details that are in plain sight. Their visual behaviour differs from that of children with ADHD or dyslexia, and their deficits are observable from a preschool age. Although further validation and research are needed, the new assessment tools are promising for early recognition and more precise diagnostic CVI assessments in clinical practice.