A human's ability to discern and identify color within their useful field of view is called color vision. Color vision defects are due to an absence of one of the pigments in the photoreceptors. The Farnsworth D-15 color vision test can be administered to assess color perception ( Kraut and McCabe 1994).
The author has led a series of experiments aimed at investigating the interaction strategies and behaviors adopted by low vision computer users during task execution. The specific task environment was visual icon identification and selection within a graphical user interface. Subjects possessed a wide range of visual capabilities and ocular pathologies (10 subjects had impaired vision and 10 subjects had normal vision). Clinical profiles for the low vision participants are shown in Table 1 ( Jacko et al. 1999).
|49||+0.9||+0.6||32||35||90||5||Congenital Cataract, Nystagmus|
|54||+1.2||+1.1||21||24||71||3||Age-related Macular Degeneration|
Visual acuity status was represented in the analyses in terms of weighted average LogMAR (WMAR) with the better eye given a weight of 0.75 and the worse eye given a weight of 0.25 ( Scott et al. 1994). Constrast sensitivity scores are represented as summations across both eyes for the number of letters identified correctly on the Pelli-Robson chart. Visual fields are depicted by