Recently, 2-D/3-D switchable displays have become the mainstream in 3-D display technologies, and people can now watch 3-D movies with a naked 2-D/3-D switchable display at home. However, some studies have indicated that people might encounter visual fatigue after enjoying a 3-D film in the theater. Although 2-D/3-D switchable technologies have been widely developed, 3-D display technologies are still lacking in ergonomic and human-care factors such as reducing visual fatigue. This study proposes a novel 2-D/3-D display autoadjustment switch system to provide biofeedback functions to reduce users' visual fatigue. In addition, the relationship between the blink rate and the visual fatigue state while watching 3-D films was investigated and quantified. In this study, liquid crystal barrier technology was used to develop a 2-D/3-D switchable display, and a wearable EOG acquisition device was also designed to monitor electro-oculography signals to estimate the blink rate. Here, the 2-D/3-D display autoadjustment criterion of the proposed system was designed according to the change in the visual fatigue state as estimated from the blink rate. Finally, the experimental results show that the proposed system could effectively reduce users' visual fatigue while watching 3-D films.