The explosion of internet technology has revolutionized education by enabling the widespread availability of self-directed online courses. However, the lack of real-time interaction in these virtual classrooms can result in decreased student attention, which is crucial for effective learning. Multiple studies have conducted measurements and analyses of learners’ attention in both traditional classroom and e-learning environments, underscoring its importance in enhancing the learning experience. This paper addresses the critical challenge of maintaining student attention in online learning by providing a comprehensive review of existing student attention assessment systems. Meanwhile, the strengths and limitations of different approaches are analyzed, and the difficulties and future directions of the research in this field are discussed.