Abstract: The growing use of dynamic interfaces for presenting medical information in hospitals has led to challenges for the elders with declining visual function, who frequently face difficulties in accessing and identifying dynamic directional triage information within healthcare settings. In order to improve the performance of elderly users in observing dynamically oriented information interfaces, a study is conducted on the factors of color contrast and information density that significantly affect the visual search performance of elderly users. Based on the hospital dynamic triage display interface and the E-prime experimental platform, visual search experiments are conducted on twenty elderly users (over 60 years old) by using color contrast and information density as independent variables. The data of visual search time, visual search correctness, clarity, and comfort ratings are collected at different levels of independent variables. Results show that the color contrast ratio of 13.7∶1 has the best visual search performance and evaluation of elderly users. However, when the value rises to 17.4∶1 and 21∶1, the performance and evaluation significantly decrease, but still better than the ratio of 8.7∶1. For the chosen font and display conditions, elderly users showed significantly better visual search performance and evaluation results at the 0.46 and 0.55 (5-6 lines) information density levels compared with others levels. Furthermore, the 0.74 (8 lines) information density level is found to be the maximum suitable density for elderly users.

Key words: dynamic orientation information interface, visual search, color contrast, information density, elderly users