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

The study did not evaluate diagnostic accuracy, reliability or validity, so it does not show how often the screen correctly identifies or misses visual perception problems. The normative sample was unusually highly educated and almost all white, so the cut-offs may not fit patients from different education or ethnicity backgrounds. The screen requires English comprehension, basic literacy and usable near vision; two participants with 0.8 logMAR near vision could not complete the reading task, and other tasks have not been tested in people with poorer near vision than 0.8 logMAR. Age and visual acuity affected some task scores, so low scores may reflect normal ageing or poor near vision rather than a visual perceptual impairment. The case examples are descriptive and small, so they cannot establish that the screen works in stroke survivors. The number of case examples is inconsistent: the text says eight cases, while Table 5 is labelled as nine cases.

The work was funded by the National Institute for Health and Care Research and the Stroke Association. Two authors are reported as funded by NIHR for this research project, and two authors held Stroke Association fellowships. The authors state the views expressed are their own and not necessarily those of NIHR, NHS or the UK Department of Health and Social Care.

Do not treat the Oxford Visual Perception Screen as a validated diagnostic test. The paper provides normative cut-offs and example cases, but it explicitly says diagnostic accuracy, reliability and validity have not yet been evaluated.