Cochlear Implant (CI) users can experience mental fatigue from the listening effort needed to process the degraded speech information delivered by the implant. Listening effort is unique to the individual CI user and may provide insight into the strengths and weaknesses of real-world speech communication. To analyze listening effort, an eye tracker lab was built utilizing pupillometry that evaluates pupil dilation to detect cognitive load. My experience working in the lab and potential applications for pupillometry in CI research will be presented. Research will have implications for better understanding factors affecting speech recognition in CI users, including predictive speech, familiarity, and talker context, and top-down strategies.