I’m now officially obsessed by cycle helmets (in addition to helicopters, crowd dynamics, Aston Martins…)
Imagine if sunglasses contained a number of small spray cans of that fast-setting builders’ foam used for sealing gaps in walls etc.
The resulting solid is fairly flexible and surprisingly impact-resistant. One might even employ the kind of foam used in non-lethal weapons to restrain rioters (but without the adhesive).
The sunglasses could be arranged so that an accelerometer detects any untoward movement towards the ground.
This would open the valves on the spray canisters, allowing the foam to escape and set within a few tens of milliseconds (ie before impact with vehicles or the road).
The effect would be to have a helmet’s protection without having to wear one.
It might later be really difficult to get out of one’s hair, but better that than a trip to an operating theatre.
Similar canisters could also be inserted into small pockets at the elbows and knees of one’s clothing.