The Oxford Visual Perception Screen: development and normative data of a standardised assessment for visual perception difficulties

Objective: We aimed to develop and standardise a practical systematic screening tool for visual perception impairments after a stroke to replace current subjective methods.Study design: A mixed methods study including test development, a cross-sectional study, and a case series.Methods: Development of the Oxford Visual Perception Screen (OxVPS) follows a published Delphi, a survey and performance data on visual perception tasks. Stakeholder feedback from patients and health professionals improved iterative prototypes. Subsequently, we collected normative data from community dwelling older volunteers without a neurological history. Our case series included patients with ocular conditions or a stroke. For each task of OxVPS, we determined 5th centile cut-off scores. We further explored effects of age, visual acuity, and gender on visual perception through Generalised Linear Models. Results: OxVPS is a 15-minute paper-and-pen assessment comprising 10 tasks including picture naming, star counting, and reading. Normative data of 107 participants demonstrated persistent high performance with most cut-offs near ceiling. Apart from the Figure Copy (p<0.001) and Global Shape Perception task (p=0.009) we found no evidence for an effect of visual acuity on OxVPS. An effect of age was only observed in the Face Recognition (p<0.001) and Reading task (p<0.001). No effects of gender were observed. A series of eight cases illustrates the interpretation of OxVPS.Conclusion: We present the Oxford Visual Perception Screen, a standardised visual perception screening tool alongside normative data and illustrative cases. OxVPS can potentially change screening for visual perception impairments in clinical practice and is available at https://oxvps.webspace.durham.ac.uk/.