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Published in Optometry and Vision Science, 2008, Vol.85, issue no. 7, pp.543-6 DOI:10.1097/OPX.0b013e31817dd06d Available from


Purpose. Damage to the nerve fiber layer or visual pathway might be expected to reduce the efficiency with which the visual system performs analysis of the ever-changing field of vision. The purpose of this article is to provide a further analysis of previously reported data (Loughman J, Davison P, Flitcroft I, Br J Ophthalmol 2007;91:1493-98.) to: (i) determine the sensitivity and specificity of a test of preattentive vision for glaucoma detection and (ii) provide a cutoff performance level that would serve to distinguish glaucoma in early cases. Methods. Three groups of observers (glaucoma, suspects, and normals) were examined, using computer-generated flicker, orientation, and vertical displacement targets to assess preattentive visual search (PAVS) efficiency. The task required rapid and accurate localization of a singularity embedded in a field of 119 homogenous distractors on either left or right hand side of a computer monitor. All subjects also completed a choice reaction time task. Results. Receiver operating characteristic curve analysis demonstrates consistently high diagnostic sensitivity and specificity values (significantly above 90% for all tasks) using the raw PAVS data and also for a novel perceptual search index (which improves the diagnostic capacity of the test). Optimal performance cutoff values for each task were also computed. Conclusions. A test of PAVS efficiency demonstrates high sensitivity and specificity to early glaucoma. Analysis incorporating the perceptual search index confirms the high diagnostic capacity of the test.

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