People who wear glasses still have a certain amount of faffing about to do when the sun shines brightly. They can have their glasses tinted or use reactolite lenses, but these can be insufficiently responsive to rapidly changing lighting conditions.
Today’s invention is glasses which have a rapidly changeable filter built in. Each lens would be backed by a very thin sheet of plastic, offset from the lens surface itself by a fraction of a millimeter. The spaces between sheet and lens would be filled with a film of water (engineered to be nearly refractively neutral). These spaces would communicate with each other via a small-bore pipe running within the bridge of the glasses. A similar pipe would be embedded in each ‘leg’ of the specs.
The flow circuit thus formed would allow water to be quickly pumped from a reservoir in a pocket, up a pipe to behind one ear, from lens to lens and back down to a different reservoir. This could be by electrical pumping or via manual bellows.
The water would be filled with dye which would shade the eyes. The concentration could be varied automatically by feedback from a light sensor located on the glasses frame.
Dyes of different colour could be used to provide a match with one’s couture du jour. Stopping the flow, with one lens red and one green, would allow the wearer to view 3-D imagery with maximal convenience.