All divers know that underwater objects look one-third closer or one-third larger. Our angle-of-view narrows, a sort of tunnel vision caused by the refraction of light when it passes from the dense medium of water to the less dense medium of air within the mask.
Years ago HydroOptix produced a mask that attempted to address this problem, but far-sighted users needed to use corrective contact lenses to focus properly on the virtual image made by the mask. It was doomed to commercial failure.
For snorkelers, a new generation of full-face masks with a built-in snorkel offers a wrap-around effect with a wide field-of-view. Such masks include the H2O Ninja mask from Hawaii and the Italian-made Ocean Reef (marketed under several well-known dive brand names).
For divers, there is a new mask on the horizon, the AAK 180, which the creators are trying to fund through IndieGoGo. It features a one-piece multi-layered curved optical-quality polycarbonate lens, said to provide 180 degrees of distortion-free vision underwater so that divers can see what's off to either side without having to turn their heads. The internal volume of this mask must be such that a leaky mask would take a lot of clearing.
AAK Diving, a small Mexican company, is attempting to raise $23,000 to launch the mask. If you invest $120 on IndieGoGo by August 10, you will get the mask if and when it is in full production. Care to gamble?