The human eye functions as a perfect microcamera with inconceivable capabilities, in comparison with every high-technology human optical invention. Due to its small dimensions and its refractive properties it has great strength and adjustability.
This category includes nearly all these problems that can be treated with the use of eyesight-correcting glasses or/and contact lenses application.
Nowadays, many of these problems are being solved within the broader section of refractive surgery, with special laser and intraocular lenses use.