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Do your spectacles mist up when you walk out of the cold into a steamy room?
Or when you open the oven door? Jason Tyrrell of Wallingford in Oxfordshire has
the answer (GB 2 362 474) with his fast-acting heated specs. Loops of thin wire
are moulded into a spectacle frame around the lenses and connected to tiny
batteries clipped into the side arms. A humidity or temperature sensor switches
on the current when there is a risk of condensation. The resistance of the thin
wire warms the frame and thus the lenses to prevent misting.