The purpose of this experimental study is to evaluate how persons perceive physical barriers and visual barrier, and how these barriers may be avoided from potentially hazardous. Eye fixation behaviors by using apparatus of eye-reflection camera are examined in dementia and mental retardation groups, in comparison with normal control group, while they are walking on corridor with three types of barriers. The results are summarized as follows. 1) Dementia group has difficulties to perceive smaller physical barrier, although all three groups fixate on bigger barrier. 2) Dementia group often fails to fixate on visual barrier, which is located on floor. 3) Dementia and Mental retardation groups often fail to fixate on wayfinding cues, due to closer barrier.
