This study examines how individual differences, user perceptions, and eye gaze relate to the use of different biomedical search interfaces. It finds that searchers look most at abstracts and that interfaces and perceptions of task difficulty affect what elements are viewed. There are also interaction effects between cognitive style/search experience and interfaces for Medical Subject Headings area of interest. The findings suggest design of search engine results pages should consider these factors and allow detection of task difficulty. Individual differences should also inform search interface design.