Several clinical conditions cause increased pre- attentive visual search (PAVS) times, implying reduced parallel search capabilities in DLB dementia and Parkinson''s disease. This book describes the effect of a number of variables on PAVS performance including optical blur, age, retinal eccentricity and perceptual learning, and critically establishes that the test remains viable in the presence of such potentially confounding variables. importantly, it also describes the efficiency of PAVS in cases of established glaucoma; glaucoma suspects and age- matched normals, determines the differential diagnostic capacity of the current test, and provides diagnostic cut-off performance indices to facilitate clinical categorisation of patients. All investigations indicate that, at the very least, the test provides a simple, rapid and accurate means of screening for the effects of glaucoma. Its capacity to differentiate glaucoma from suspects suggests its diagnostic ability extends beyond that achieved by conventional perimetry.