Wearables are getting lighter and lighter. Technology advancements have made processors small enough to put on glasses and watches. As the trend continues, we will see wearables and fashion overlap to a point where you might not even be able to tell if someone has a wearable on or just a pair of regular glasses. Perhaps the wearable will eventually be exclusively in a contact lens. Until then, companies are revamping the wearables with enhancements almost on a monthly basis. One company that is advancing wearable displays is WaveOptics. WaveOptics is working on a lightweight display that is only 7 grams. Although the field of view is relatively small, the fact that it is only 7 grams is intriguing. WaveOptivcs, a UK based company, has been developing lightweight wearables displays a while now, and their latest display is called Katana. A great name choice. According to Wikipedia, katana is a Japanese sword characterized by a curved, single-edged blade with a circular or squared guard and long grip to accommodate two hands. It was used by the samurai of ancient and feudal Japan. Here are the specs of the Katana from WaveOptics compared to their previous glasses:  
Feature Katana Vulcan Odin
Thickness 1.15mm 3.1mm 2.65mm
Weight 7g 12g 17g
Field of View (FoV) Up to 30? 28? and 40? 60?
Full Colour? Yes Yes Yes
Ideal for: Lightweight, low cost, low power smart glasses design Lightweight smart glasses design where colour and complexity of AR headset is more than just notification-based use cases. Full colour, ultra-high field of view & periphery vision.
  BrighterSight is looking forward to trying out the thinnest and lightest waveguide.   Read more here from the press release : https://enhancedworld.com/2020/02/03/waveoptics-launches-waveguide-that-will-bring-ar-wearables-to-the-mass-market/