A 'web app' for diagnosing hemianopia.
BACKGROUND
Hemianopia commonly complicates stroke and, less frequently, head injury and brain tumours. Patients' activities of daily living are often affected although these can be ameliorated by appropriate behavioural therapy. Identifying a field defect is the first step in the rehabilitation process. An online visual field test (an 'app') was developed as part of a free to use web based therapy site for patients with hemianopic alexia, called Read-Right (http://www.readright.ucl.ac.uk). This study is an attempt to validate this test by comparing with a clinical 'gold standard'-the Humphrey automated visual field analyser.


METHODS
22 patients had their visual fields assessed with both techniques on the same day. The criterion validity of the Read-Right was examined by comparing it with Humphrey 10-2 and 24-2 perimetry using the following measures: (1) sensitivity and specificity; (2) κ statistics; and (3) intraclass correlation.


RESULTS
Read-Right demonstrated high sensitivity and specificity, particularly for the undamaged field. In the damaged field, κ values were highly significant, especially for points along the horizontal meridian. The intraclass correlation score for the damaged field indicated excellent correlation between the two tests. Read-Right perimetry performed well on all measures. It had a tendency to under call damaged points offset from the horizontal meridian, and this and other aspects of the test will be revamped.


CONCLUSIONS
Read-Right is not designed to replace standardised visual perimetry; it does, however, offer a quick and easy assessment that can be used to screen patients. The test is available as part of two free to use web based therapy applications.
Institute of Neurology, University College London, London, UK.
Nato
N
Koiava
Yean-Hoon
YH
Ong
Maurice M
MM
Brown
James
J
Acheson
G T
GT
Plant
Alexander P
AP
Leff
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006423:Hemianopsia / Q000175:diagnosis* / Q000503:physiopathology; D006801:Humans; D020407:Internet; D008297:Male; D008491:Medical Informatics Applications; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D012984:Software; D014787:Vision Tests; D015348:Vision, Binocular; D014794:Visual Fields