To solve a problem wherein the visual acuity lowers by watching a monitor for a long period of time caused by the popularization of PCs and the cellular phone instead of the television recently, the disorder called "game brain" is developed, and increasing number of users have the problems.

A person can obtain a sense different from the original visual field such as an illusion so that, if viewing even a nearby screen at a distant screen, the person has the illusion of viewing the distant place naturally (instinctively) and highly possibly makes the muscles of the lens act for viewing the long distance. In a state where an object is viewed well when separating it, the person naturally (instinctively) sets the visual field at a distance, so that when an image invisible in the vicinity is corrected to such an extent of being non-recognizable and projected on the monitor, the person naturally (instinctively) sets the visual field far from the monitor to prevent the lowering of the visual acuity. The electronic characters and figures are thus moved against the intention of the user so as to prevent the both of the lowered visual acuity and the so-called "game brain".