1. A multifocal ophthalmic lens, called a HOPSA-lens, for training a person's accommodative and vergence systems, said HOPSA-lens is duly secured in a retainer device suitable for wearing by the person subjected to said training being placed in front of his/her eyes; said HOPSA-lens has a variable optical power, a geometrical center, and a horizontal meridian extending through said geometrical center substantially horizontally in relation to said retainer device with a predetermined deviation; said HOPSA-lens is characterized with a plurality of vertical profiles perpendicular to said horizontal meridian; said HOPSA-lens comprises: a predetermined number N of near vision zones, called N-zones, each said N-zone has a center located on the horizontal meridian and predetermined dimensions; a predetermined number F of far vision zones, called F-zones, each said F-zone has a center located on the horizontal meridian and predetermined dimensions; wherein each said F-zone being adjacent along said horizontal meridian to at least one said N-zone and vice-versa, thereby forming an N-F pair of zones; and a respective number of transitional corridors having predetermined dimensions, each said transitional corridor is disposed between the F and the N zones of each said N-F pair; wherein said HOPSA-lens is characterized in that the optical power steplessly alternates substantially along said horizontal meridian only within said HOPSA-lens from any said N zone to the corresponding adjacent said F zone and vice-versa, while the optical power is invariable for each vertical profile from said plurality of vertical profiles.