Eyerobics grid glasses are made from thick, high-quality plastic. The grid is designed in dark, durable plastic that absorbs much of the incoming light, minimizing refraction.
The lenses feature a network of stenopeic holes in a hexagonal pattern. The grid itself is slightly concave/convex—this shape reflects the cellular structure of the retina.
A stenopeic hole, well known in optics, acts like an artificial pupil. The eye naturally adjusts focus much like a camera.
When you use pinhole glasses, each hole narrows the eye's aperture to a single small opening. This encourages your eye to "focus" the image on its own.