The alignment of the two is critical for clear vision, but being a fluid-filled ball, it is not going to stay in perfect alignment without an active control mechanism.

Your eyeball is in a constant state of adjustment based on where the light focuses, on, in front of, or behind the retina.

If light focuses in front of the retina, the eyeball will try to shorten, axial reduction.

If light focuses behind the retina, the eyeball will try to lengthen, axial elongation.

One reason light might focus behind the retina is your glasses.

Glasses to control nearsightedness will cause some of the light to focus behind the retina, called hyperopic defocus.

This sends a signal to your eyeballs to increase axial length, elongating the eyeball to correct what it perceives as being too short.

Now that your eyeball is longer, light focuses even further in front of the retina, and you're even more nearsighted than before.

Higher and higher correction glasses can continue to cause the eyeball to elongate.

Curious to learn more?

Dive into the science and studies on Google Scholar at scholar.google.com.

Find many thousands of peer-reviewed clinical studies exploring axial elongation caused by glasses.

Search for lens-induced myopia.

Also explore the keywords pseudomyopia and NITM, near-induced transient myopia.