The video you just watched shows how hyperopic defocus in a corrected myopic child can lead to the elongation of the globe. This elongation increases myopia in children.
IF THIS HYPEROPIC DEFOCUS CAN BE REMOVED, THEN THE STIMULUS FOR ELONGATION CAN BE REMOVED. If the stimulus for elongation is removed, then myopic progression or pathological myopia can be halted or controlled.
Hence, in managing myopic progression, special lenses that move the defocused hyperopic images to the retina have been developed. They are used as adjunct therapies for managing myopic progression.
These spectacle lenses effectively cancel out the hyperopic defocus. This moves the image shell forward onto the retina. By so doing, it reduces or removes the stimuli for the eye to elongate.
It is worth noting that:
1. RPHD also occurs when standard spectacle or contact lenses are used by children. Both approaches to myopic correction may also contribute to myopic progression in some children.
2. Due to the shape of some eyes, the periphery may have a natural myopic defocus.