PURPOSE: To provide a preventive implement for preventing shortsightedness and hyperopia and the preventing method using its implement by giving externally, what is called remote vision at a suitable interval in an adjacent vision state.
CONSTITUTION: The preventive implement 1 is constituted by forming a pair of vision distance adjusting means 2 being variable to a non-lens state and a lens state for giving a prescribed focal distance, and also, forming a control means 4 for controlling both these vision distance adjusting means 2. Also, in a state that both the vision distance adjusting means 2 of this preventive implement are installed in spectacles and used, remote vision is given with regard to a prescribed time in an adjacent vision state by controlling programmatically the non-lens state and the lens state of both the vision distance adjusting means 2 by the control means 4.