Image shells on the retina. Once the eye elongates in myopia, optical images from spherical lenses no longer fall on the retinal plane. The peripheral images are out of focus falling on a plane behind the retina. It is thought that the relative hyperopic error created is the stimulus for axial elongation. Current optical treatments move the peripheral focus in front of the retina
https://www.researchgate.net/figure/Image-shells-on-the-reti...

Figure 1: Image shell created when a myopic refractive error is corrected: a) with a conventional single vision lens; b) with an ‘ideal’ lens which accounts for the prolate shape of the eye / relative peripheral hyperopia. Adapted from Smith (2011)
https://www.eyenews.uk.com/features/optometry/post/are-we-sh...





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Note added at 19 hrs (2021-07-21 12:40:59 GMT)
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With traditional spectacle correction in myopia, light is focused on the macula, allowing for best visual acuity; however, in the retinal periphery, light falls behind the retina. The result is a peripheral image shell formed that falls behind the retina.
https://webcache.googleusercontent.com/search?q=cache:GWIFVi...