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New clinical measure to assess the visual awareness in peripheral field loss (PFL)
Author(s) -
ALSHAGHTHRAH A,
DICKINSON C,
MURRAY I
Publication year - 2012
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.2012.f069.x
Subject(s) - quartile , stimulus (psychology) , audiology , visual field , eccentricity (behavior) , psychology , medicine , simulation , computer science , statistics , mathematics , ophthalmology , social psychology , cognitive psychology , confidence interval
Purpose Individuals with PFL have problems moving about, and there are some optical aids that are proposed to enhance mobility performance. However, currently the efficacy of these aids cannot be determined without extended wear. This study aims to design a new clinical measure to assess the visual awareness in PFL patients, so that this new test could be used to determine the efficacy of optical aids in a clinical setting Methods PFL was simulated using goggles in 50 normally‐sighted subjects. The simulated field of view (FoV) was varied from 5° to 20°. In the new test, observers were asked to search for a stimulus in a 60° field of view and the detection time (DT) & detection efficiency (DE) (DE is the Inter‐quartile range of the DT responses at each eccentricity for every subject) were measured. Head and eye movements were allowed and the presentation time was unlimited. Clinical validity was investigated by correlating the DT and DE scores with the percentage preferred walking speed (PPWS) and the number of collisions on an indoor mobility course Results The DT and DE scores were inversely correlated with the FoV (r=‐0.60; p<0.0001, for both of them). These scores varied linearly with eccentricity. The DE was inversely correlated with the PPWS (r=‐0.50; p<0.0001) and positively with the collisions score on the indoor mobility course (r=0.50; p<0.0001) Conclusion The awareness test was sensitive to FoV and stimulus eccentricity. The test results have good correlation with mobility course scores which indicates that the new test is valid. The test is unique, quick, and simple to deliver. The new visual awareness test could be a valuable tool to test the efficacy of optical aids that are intended to enhance mobility performance in PFL patients.