However, augmented reality glasses like the Microsoft HoloLens 2, Google Glass Enterprise 2 and Magic Leap 2 are already being used commercially. But low display resolution, small field-of-view, short battery life, bulky form factors and high costs have restricted them to a limited range of tasks.
For the technology to achieve widespread use, it needs to be indistinguishable from a normal pair of glasses. This will require massive reductions in size, power consumption and cost. Breakthroughs in optics,12 energy-efficient computing and wireless communication will all be crucial, but the biggest challenge is safely dissipating heat from on-board electronics.13 Another outstanding problem is finding ways for virtual objects to convincingly occlude real world ones using optical technology.
It may be possible to sidestep some hardware limitations through tricks like “foveated rendering”14 where the eyes are tracked and only the area of focus is rendered in high definition. Spatial audio could counteract tunnel vision by alerting people to things outside their visual field, and physiological monitoring through EEG and skin conductance could help understand the user's intention or cognitive state to optimise the information displayed. Pairing smart glasses with a companion device, such as a smartphone that does the bulk of the processing, could help get around limited on-board processing capacity.
Creating truly immersive augmented reality will also require breakthroughs in haptics technologies, which mimic physical sensation. Today's experimental haptic devices are focussed on specific tactile experiences and generalized haptics that can mimic a wide variety of sensations remain elusive, though ultrasonic devices show promise.15 In the distant future augmented reality may eventually be mediated by smart contact lenses rather than glasses,16 or even via brain-machine interfaces connected directly to the nervous system.
