Eyeglasses aren't complicated. You go to the optician's office, get your eyesight evaluated and, in an hour or so, leave with a new pair of specs hanging on your face. Those glasses stay in use until your eyesight either worsens or improves (or breaks after being sat on). And only those with the same vision problems as you can borrow them.
Adlens changes all that, bringing the ability to change the power of the lens dynamically. That means no need to be refitted with new lenses when your actual eyesight changes. It also means a more convenient pair of specs that you can adjust, depending on lighting, distance and other similar conditions.
The glasses are based on Prof. Joshua Silver's work on adaptive lenses, which bear an entirely different construction from traditional units. Instead of solid mounds of glass, each lens comes with fluid-filled interiors; changing the volume of liquid inside alters its shape and how it affects your eyesight.
Two models are available: Adlens Reader and Adlens Universal. Both can be adjusted by turning the dial on the corner of one side, allowing you to find the right correction on the fly. The former are regular reading glasses that can be adjusted to compensate for lighting conditions, eye fatigue and distance, while the latter allows you to modify vision across a wide 8 diopter range, for both near and far.
Currently, Adlens is marketed strictly in developing countries, where regular access to optical work might not be as readily available as in other places. Because of their flexibility, a single pair of glasses can be shared by different people, apart from being usable for many years.