Eye elongation after reading very close could be visible as spherical aberration

Spherical aberration is visible as blurred image over the clear one.

It appears after reading very close (20-25 cm) in full correction for say <15 min.

Then, it slowly disappears while viewing at distance in the next minute or so.

It is well-visible only at points of light in the dark periphery (night time).

That matches the findings of study “New study on axial length decrease!” that eye elongates while viewing close (and that elongation disappears in short time).

Interesting. You tried it yourself?

can hyperopic defocus occur if emmetropia is seeing at very close range?

Yesterday evening I tried it because I was too lazy to control how close I hold my tablet.

“Hyperopic defocus” is a very wide term. Light physics is quite broader IMO, because of many higher order aberration containing everything you’d ever want, including “myopic/hyperopic defocus”.

My opinion about globe elongation is quite different than EndMyopia one. Based on research and personal feelings/experience, I would claim that eye somehow acts like a “bone”, “absorbing” often repeated mechanical pressure created by accommodation or AF (these consist both from ciliary and extrinsic muscles). For example, how corneal astigmatism occurs or gets worse. If someone forcefully closes eyelid for a long time every day, corneal astigmatism induces at the axis palpebral fissure lies in (e.g. 173 degrees). Why not in all people? Vertical muscles should inflate vertical meridian of cornea. If they fail to certain degree, it’s easy to induce WTR astigmatism by slightest mechanical stimuli.

I used to search theories other than EndMyopia because I never worn cylinders more than 1.25 left and 2.25 right, but my astigmatism increased further to R 2.75 L 1.75, and I also feel some decrease in visual acuity seeing through older contact lenses prescription.

It is a mystery for me how does eye react to defocus. Maybe intraocular pressure goes into play. Say, if I try to wear 2 diopters more minus and refusing accommodation, I get strange eye pain, comparable to when I touch very soft needles (just blurred like 2 diopters less minus, however it’s hard to fully relax ciliary muscle when you wear severe overcorrection for purposes to see a severe hyperopic blur).

Short-term elongation from near focus demand is well documented to be from choroidal thinning. This has no effect on any lens, and thus no effect on their aberrations.

Therefore, the title of this thread is physically impossible.

If you self-experiment with extreme near focus, you are completely dominated by ciliary action. This was almost certainly NITM decay.

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There is a book on this forum site: [URL removed]

The book claims it is well documented and explored that myopic eye enlargement is from stretching or decrease of density of ocular structures, and not growth or new cell formation.

Then, I come to conclusions.

Why choroid thins? The sclera stretches.
Why the sclera stretches? Because of mechanical tension.
What is capable to produce tension, to say stretch or un-stretch the sclera? Extrinsic muscles, intraocular pressure, maybe ciliary muscle.

Defocus theory can’t explain why I get slightly more myopic refraction after sleeping.

Mechanical theory, yes.

Eyes cross when I falling asleep while looking down or not up.
Crossed eyes produce accommodation.
Accommodation tenses up ciliary muscle.
There is a positive relation between ciliary muscle and oblique muscles.
Prolonged or chronic contraction of the last results in gradual increase in axial length, like chronic winking by first increases astigmatism only temporarily, then permanently.

That is what I collected during my research.
Certainly, these are only hypotheses or predications.
But, the documentation you cited seem to be also too one-sided or incomplete, because it lacks the view of eye as a whole, omitting how all those processes relate to each other.

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Yes, this is very likely true. (Though I’m not sure how you delineate “growth” here.) But this is about long-term changes to the sclera. It’s happens in months, rather than minutes or hours.

Yea, that’s more likely on intraocular pressure or something like that.

On purely externally mechanical theories, there are a number of rhesus monkey studies where the eyes do things that cannot be explained this way. For example, uneven lenses resulting in uneven eye shape, or eyes adapting without the optic nerve. The eye seems to have some capability of locally changing the shape of the sclera from inside, and that mechanism seems to be the main cause of axial myopia.

Much of the difficulty here is to find the long-term signal in all the short-term noise. We have a whole bunch of ways to affect myopia to some degree for some time, but most of them don’t lead to continuous improvement. The big question is: which things cause the lasting scleral shape changes?

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I am not a fan of any theory, as I said already. I mostly done my research and happy with things I already know. Thanks for your part, all thoughts are valuable for me.

I am rather an ad hoc researcher, researching only things I really need.
So, I wrote my part and going out from this discussion.