Relationship between changes in crystalline lens shape and axial elongation in young children.

Relationship between changes in crystalline lens shape and axial elongation in young chilren.

Ishii K, Yamanari M, Iwata H, Yasuno Y, Oshika T.

Department of Ophthalmology, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan.

Invest Ophthalmol Vis Sci. 2013 Jan 28;54(1):771-7.

This study of 25 children highlights the interaction between the lens and the length of the eyeball in the development of myopia.  It's not just that the eyeball is longer; the lens also works differently in myopic children, affecting the length of the eyeball, and playing a role in the development and progression of myopia.

From the text:
"CONCLUSIONS:
Axial elongation is related to the entire contour of the crystalline lens. This result shows that axial elongation progresses in parallel to change in the crystalline lens shape."

Link to abstrract:
http://www.ncbi.nlm.nih.gov/pubmed/23307966

Other articles that highlight the role of the lens in the development of myopia:

How does nearsightedness develop in children?." ScienceDaily. ScienceDaily, 1 March 2012. http://www.sciencedaily.com/releases/2012/03/120301113258.htm

Myopia: It's Not Just the Length, but the Lens
Myopia is commonly described as having an eyeball that is “too long.” Not exactly.

By Colleen Mullarkey, Senior Editorhttp://www.revoptom.com/content/c/33495/x

Crystalline Lens Power in Myopia
GARNER, L F O.D., Ph.D.; YAP, M O.D., Ph.D.; SCOTT, R O.D., M.Sc.http://journals.lww.com/optvissci/Abstract/1992/11000/Crystalline_Lens_Power_in_Myopia.5.aspx

Current and Future Developments in Myopia Control Researchers continue to seek effective methods to slow the progression of myopia.

Current and Future Developments in Myopia Control
Researchers continue to seek effective methods to slow the progression of myopia.
By Jeffrey J. Walline, OD, PhD, FAAO
Contact Lens Spectrum, Volume: 27 , Issue: October 2012, page(s): 34 - 38

This article summarizes the current approaches to myopia control, and lists various studies. Atropine has a high success rate, but the effect may be short-lived and its side effects long term are not known.

Orthokeratology and dual focus contact lenses appear to have some impact in controlling myopia in children.  

http://www.clspectrum.com/printarticle.aspx?articleID=107513

Light Exposure and Physical Activity in Myopic and Emmetropic Children.

Light Exposure and Physical Activity in Myopic and Emmetropic Children.

Read SA, Collins MJ, Vincent SJ.
Optom Vis Sci. 2014 Jan 9. 

This study measured ambient light exposure and physical activity of 102 children, 10 to 15 years old over a 2-week period, using a measuring device worn on the wrist.  The device registered much less light exposure and time spent in bright light conditions among myopic children, and no significant difference in daily physical activity between myopic and emmetropic (not myopic) children.  Other studies have also found that myopic children seem to spend less time in natural sunlight and bright light conditions.

Link to abstract:
http://www.ncbi.nlm.nih.gov/pubmed/24413273

Integration of Defocus by Dual Power Fresnel Lenses Inhibits Myopia in the Mammalian Eye

Integration of Defocus by Dual Power Fresnel Lenses Inhibits Myopia in the Mammalian Eye.Invest Ophthalmol Vis Sci. 2014 Jan 7McFadden SA, Tse DY, Bowrey HE, Leotta AJ, Lam CS, Wildsoet CF, To CH.

This study found that in guinea pigs, myopia can be induced and then reduced by using plus lenses and dual focus fresnel lenses.  In this study, like in many other animal studies, this reduction of myopia through the use of plus lenses seems to be fairly effective, but it's on induced myopia, so it might not be as effective in human myopia, which is not induced.  The question that remains for me is, what are the triggers that begin the process of developing myopia?  Since there appears to be a very strong genetic component to human myopia, and many have proposed that genetic predispositions are triggered by environmental factors, what are the triggers?  And in the cases where these genetic predispositions exist, can environmental changes (like more sunlight as is suggested in many studies, or plus lenses, for example) be as effective as in the cases of induced myopia?

Link: http://www.ncbi.nlm.nih.gov/pubmed/24398103