In one aspect, a device may include at least one processor, a camera accessible to the at least one processor, and storage accessible to the at least one processor. The storage may include instructions executable by the at least one processor to receive input from the camera and to determine, based on the input from the camera, that a change in the dilation of a user's pupils has occurred. The instructions may also be executable to perform at least one action at a device based on the determination, where the at least one action may be related to the user's interest in at least a portion of content presented using the device.