We determined the visual efficiency and visual discomfort for users of a typical transitional space in luminous climates. The subject moves from a brighter exterior to a dimmer interior, facing an abrupt change in the level of lighting as a potential functional vision barrier, mainly for ageing people. We measured suprathreshold visual efficiency in different age groups, recognising two Landolt ring orientations and answering some visual discomfort questions. Results show: oldest group (60–67) needed more than 3 times the time required by the youngest group (25–30) to perform the task but, in terms of discomfort, there are no noticeable effects regarding the disturbance or the sensation of reduction of mobility produced by the lighting changes in the transitional space among the three different groups.