Abstract: A heads-up display for an item of eyewear includes a mounting means configured to mount the heads-up display to the item of eyewear; at least one sensor configured to obtain performance data; a processing unit operatively connected to the at least one sensor, and configured to process said performance data and to generate an image from said performance data; a micro display unit operatively connected to the processing unit, and configured to display the image under the control of the processing unit; and, an optical wave guide in optical communication with the micro display unit, and configured to route the image from the micro display into a field of view of a wearer of the item of eyewear. The heads-up display is configured to overlay the image into the line of sight of the wearer, such that the wearer can view their surrounding environment at the same time as the image, and therefore view their performance data real-time.