Mi Contact Lens is being developed by a California startup Smartlens, and is based on a prototype that was previously created at Stanford University. Whereas the Stanford device had to be surgically placed in the eye, the miLens is a soft contact lens which is put in and taken out on a daily basis, like any other contact lens.
Incorporated in the Mi contact lens is a sealed microfuidic channel which runs around the perimeter of the wearer's limbus in a ring. That channel is partially filled with a non-toxic liquid, and has graduated numerical markings which indicate IOP measurement units.
As the user's intraocular pressure increases, it causes their cornea to bulge out and press on the miLens. That pressure forces the liquid in the lens up through the channel – the greater the pressure, the farther the liquid will go. Utilizing a camera, users get a close-up shot of the miLens. By seeing what number on the channel the liquid has reached, a real-time IOP reading is generated at will.