When viewing (observing) any near distant object, the visual axis change their converging (since they can’t stay parallel) so as to let the image of the object fall onto central fovea of both eyes. As explained in PV SYSTEM, central fovea is a very little retinal part where the image must fall so as to be focused perfectly: the further it falls the more fogging increases (as it happens in the case of errors in muscular co-ordination and therefore convergence).

Training the extrinsic ocular muscles through working at the widest range of ocular movement together with the exercises of fixation/peripheral convergence* (fixing at a point and trying to maintain binocular vision) is aimed at improving the level of ocular convergence (which is often jeopardised so much that it becomes strabismus/squint as it happened to the author)

The Stimulation, which in masterly happens using the lenses– the positive ones for the myopes and the negative ones for the hyperopes – leads to the process of gradual adaptation to the training stimulus (see the principles of Overloading and SAID Principle – Specific Adaptation to the Imposed Demand), with consequent gradual lessening of both myopia and hyperopia.

* Keep in mind: As training with peripheral fixation isn’t meant better peripheral vision but better central fixation of an object/point which is at the extreme parts of visual field: this concept has nothing to do with the one of peripheral vision, which means perceiving the objects at the edge of the visual field.