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I have a background in physics, which carries with it the danger of over-simplying models to make them tractable. (See wikipedia:Spherical cow). All this messy biology stuff really gets in the way of a nice story.

I would like to think that I'm reasonably capable of expressing technical details succinctly (eventually). However, since I'm brand new to EM, I'm not quite au fait with the details (and orthodoxy) that is being described in the wiki. Hence my conflict between boldness and timidity in editing pages.

Oh, and if I edit or delete something you've written and you think I'm wrong, do say so. And put it back. (And if I delete it again without talking to you about it, call me out on it. It will certainly be because I've forgotten that I'd deleted it previously, and forgot to check the diffs to see that it had been re-added for a good reason.)

This seems like a good place to collect interesting papers that I don't want to lose references to...

Use to generate citations.

One useful trick to find papers hidden behind a journal paywall... the author (or supervisor, for a PhD student) might keep copies on their professional home page. (Such as at their institute.)

Active talk page discussions

Interesting videos

shows details of zonnules during accommodation and de-accommodation.

review paper on the growth mechanism

Wallman J, Winawer J (2004). "Homeostasis of eye growth and the question of myopia". Neuron. 43 (4): 447–68. doi:10.1016/j.neuron.2004.08.008. PMID 15312645.

A review paper:

As with other organs, the eye's growth is regulated by homeostatic control mechanisms. Unlike other organs, the eye relies on vision as a principal input  to guide growth. In this review, we consider several implications of this visual guidance. First, we compare the regulation of eye growth to that of other organs. Second, we ask how the visual system derives signals that distinguish the blur of an eye too large from one too small. Third, we ask what cascade of chemical signals constitutes this growth control system. Finally, if the match between the length and optics of the eye is under homeostatic control, why do children so commonly develop myopia, and why does the myopia not limit itself? Long-neglected studies may provide an answer to this last question.

Accommodation causes elongation ?

Read SA, Collins MJ, Woodman EC, Cheong SH (2010). "Axial length changes during accommodation in myopes and emmetropes". Optom Vis Sci. 87 (9): 656–62. doi:10.1097/OPX.0b013e3181e87dd3. PMID 20562668.CS1 maint: multiple names: authors list (link)

To investigate the influence of accommodation on axial length (AXL) and a comprehensive range of ocular biometric parameters) in populations of young adult myopic and emmetropic subjects.

Mallen EA, Kashyap P, Hampson KM (2006). "Transient Axial Length Change during the Accommodation Response in Young Adults". Invest Ophthalmol Vis Sci. 47 (3): 1251–4. doi:10.1167/iovs.05-1086. PMID 16505066.CS1 maint: multiple names: authors list (link)

This is the one Jake mentions in blog at

Also (don't have a doi for this one):

  • The first 4 references are for other studies which link near work and accommodation to myopia

Exaggerated longitudinal eye growth is assumed to play an important role in the development of myopia. A significant correlation between refraction and amount of near-work has been reported.

(Off-topic but confirmation biasy...)

A really really old paper (1932)

Based on the hypothesis that progression of myopia may result from tension of the extraocular muscles during prolonged convergence in near work ...

...  The human eye elongates slightly during accommodation,... suggesting that prolonged accommodation might lead to a permanent increase in eye length and myopia. On this basis, reducing accommodative effort might act to reduce myopia progression.

But maybe it's convergence, not accommodation

Bayramlar H, Cekiç O, Hepşen IF (1999). "Does convergence, not accommodation, cause axial-length elongation at near? A biometric study in teens". Ophthalmic Res. 31 (4): 304–8. doi:10.1159/000055551. PMID 10325546.CS1 maint: multiple names: authors list (link)

Myopic defocus is most effective in the evening ?

A really interesting result that watching TV in the evening with undercorrection will magically cure myopia ??!!??

Moderiano D, Do M, Hobbs S, Lam V, Sarin S, Alonso-Caneiro D; et al. (2019). "Influence of the time of day on axial length and choroidal thickness changes to hyperopic and myopic defocus in human eyes". Exp Eye Res. 182: 125–136. doi:10.1016/j.exer.2019.03.019. PMID 30926510.CS1 maint: multiple names: authors list (link)


  • Ocular response to defocus varies depending on the time of day in human subjects.
  • Evening exposure to myopic defocus causes a larger reduction in axial length.

Also Nickla DL, Jordan K, Yang J, Totonelly K (2017). "Brief hyperopic defocus or form deprivation have varying effects on eye growth and ocular rhythms depending on the time-of-day of exposure". Exp Eye Res. 161: 132–142. doi:10.1016/j.exer.2017.06.003. PMC 5557081. PMID 28596085.CS1 maint: multiple names: authors list (link)

It is generally accepted that myopic defocus is a more potent signal to the emmetropization system than hyperopic defocus: one hour per day of myopic defocus cancels out 11 h of hyperopic defocus.

Chakraborty R, Read SA, Collins MJ (2012). "Monocular myopic defocus and daily changes in axial length and choroidal thickness of human eyes". Exp Eye Res. 103: 47–54. doi:10.1016/j.exer.2012.08.002. PMID 22971342.CS1 maint: multiple names: authors list (link)

Nickla DL, Thai P, Zanzerkia Trahan R, Totonelly K (2017). "Myopic defocus in the evening is more effective at inhibiting eye growth than defocus in the morning: Effects on rhythms in axial length and choroid thickness in chicks". Exp Eye Res. 154: 104–115. doi:10.1016/j.exer.2016.11.012. PMC 5359047. PMID 27845062.CS1 maint: multiple names: authors list (link)

hyperopic defocus (human)

Read SA, Collins MJ, Sander BP (2010). "Human optical axial length and defocus". Invest Ophthalmol Vis Sci. 51 (12): 6262–9. doi:10.1167/iovs.10-5457. PMID 20592235.CS1 maint: multiple names: authors list (link)

This is the one Jake cites on  It's monocular, where the other eye is required to look into the distance in order to inhibit accommodation.

Delshad S, Collins MJ, Read SA, Vincent SJ (2020). "The time course of the onset and recovery of axial length changes in response to imposed defocus". Sci Rep. 10 (1): 8322. doi:10.1038/s41598-020-65151-5. PMC 7239843. PMID 32433541.CS1 maint: multiple names: authors list (link)

This is the nice one with the maltese cross

Nearwork-induced transient myopia

so many to choose from...

Ciuffreda KJ, Vasudevan B (2008). "Nearwork-induced transient myopia (NITM) and permanent myopia--is there a link?". Ophthalmic Physiol Opt. 28 (2): 103–14. doi:10.1111/j.1475-1313.2008.00550.x. PMID 18339041.

 Myopia is a worldwide public health problem. However, its understanding is incomplete, and many of its preventative and therapeutic aspects remain controversial. Nearwork is a primary, environmentally based factor in the aetiology of permanent myopia (PM), with nearwork‐induced transient myopia (NITM) being a possible contributory component. A relationship between PM and NITM has been suggested, but that connection has remained somewhat indirect and elusive. However, based on recent converging evidence from clinical, laboratory and modelling studies, a five‐fold argument will be advanced for a possible link between PM and NITM.
It is well‐established that nearwork is a primary, environmentally based factor in the development and progression of myopia...

Evidence that it is elongation that causes myopia

McBrien NA, Adams DW (1997). "A longitudinal investigation of adult-onset and adult-progression of myopia in an occupational group. Refractive and biometric findings". Invest Ophthalmol Vis Sci. 38 (2): 321–33. PMID 9040464.

Conclusions: The structural cause of adult-onset and adult-progression of myopia is vitreous chamber elongation.

biofeedback = AF ? (just first page of a letter to the editor, complaining about) which disses the idea


A review : Read SA, Collins MJ, Carney LG (2007). "A review of astigmatism and its possible genesis". Clin Exp Optom. 90 (1): 5–19. doi:10.1111/j.1444-0938.2007.00112.x. PMID 17177660.CS1 maint: multiple names: authors list (link)

Evidence that the internal optics compensate for corneal errors ? (ref 15 of the review)

pubmed offered this as a similar study:

It is well known that the aberrations of the cornea are partially compensated by the aberrations of the internal optics of the eye (primarily the crystalline lens) in young subjects. This effect has been found not only for the spherical aberration, but also for horizontal coma...

Artal P, Benito A, Tabernero J (2006). "The human eye is an example of robust optical design". J Vis. 6 (1): 1–7. doi:10.1167/6.1.1. PMID 16489854.CS1 maint: multiple names: authors list (link)

 ... indicating that the internal ocular optics (mainly the crystalline lens) play a significant role in compensating for the corneal aberrations, thereby producing an improved retinal image. In this paper, we show that this compensation is larger in the less optically centered eyes that mostly correspond to hyperopic eyes. This suggests a type of mechanism in the eye's design that is the most likely responsible for this compensation. Spherical aberration of the cornea is partially compensated by that of the lens in most eyes...