Digital nudging is building on the nudging concept established by behavioral economics. Although nudging and digital nudging have received increasing attention from academia and practitioners, there is evidence that it might be less effective than expected. This lacking effectiveness is in part due to not noticing and cognitively processing the digital nudge. Thus, more invasive methods are needed, and we suggest that using attentive user interfaces based on eye-tracking technology can further enhance the impact of digital nudges. These will be particularly effective when users would have missed out on certain digital nudges presented on the user interface. Hence, we propose a design science project with a focus on the evaluation phase which includes the theoretical underpinning as well as an experimental design of attentive user interfaces for digital nudges. Thereby, we build on an e-commerce context and suggest giving customers, that do not recognize a digital nudge, interactive real-time feedback. Our artifact can be used by practitioners to improve the usability of digital interfaces.