Video lectures are one of the primary learning resources embedded in e-learning environments. Many universities prepare video lectures and share them as open course materials with students. In order to make the learning process more efficient and effective, it is very important to design and personalize those learning resources for learners, taking into their needs and cognitive differences. The literature regarding how cognitively diverse users benefit from which media design is scarce. Therefore, the purpose of this research is to explore the effect of video lectures types (voice over type, picture-in-picture type, and screencast type) and learners' sustained attention levels (low, and high) on their learning performance in an e-learning environment. The research was designed as a 2 x 3 factorial design. In addition, learners' eye movements have been recorded during study sessions. Results indicate that main effect of learners' sustained attention levels and video lecture types on learning performance were significant. Furthermore, it was observed that both for the students with high level of sustained attention and for the students with low level of sustained attention, the use of picture-in-picture types of video lectures led higher learning performance scores. Similarly, the eye tracking analyses also supported this finding.