Difference between revisions of Blur
mNo edit summary |
(move the ref to the defocus study in with the others, using the sumsearch.org/cite tool) |
||
| Line 4: | Line 4: | ||
==Myopic vs Hyperopic Blur== | ==Myopic vs Hyperopic Blur== | ||
Myopic blur is the type of blur normally experienced by people with uncompensated [[myopia]]. Hyperopic blur is the type normally experienced by people with uncompensated hyperopia. In order to induce blur, use a lens with the opposite [[diopter]] sign as the lens normally used for blur correction, so a plus lens will give myopic blur to an [[emmetrope]]. A weak negative lens will give myopic blur to a myope. | Myopic blur is the type of blur normally experienced by people with uncompensated [[myopia]]. Hyperopic blur is the type normally experienced by people with uncompensated hyperopia. In order to induce blur, use a lens with the opposite [[diopter]] sign as the lens normally used for blur correction, so a plus lens will give myopic blur to an [[emmetrope]]. A weak negative lens will give myopic blur to a myope. | ||
==Diffusion blur== | ==Diffusion blur== | ||
| Line 19: | Line 13: | ||
==Defocus as a stimulus for eye length changes== | ==Defocus as a stimulus for eye length changes== | ||
The eye needs stimulus to make corrective changes. Studies have shown that inducing defocus can induce axial lengthening and shortening. | The eye needs stimulus to make corrective changes. Studies have shown that inducing defocus can induce axial lengthening and shortening. | ||
<ref name="pmid29749514">{{cite journal| author=Zhou YY, Chun RKM, Wang JC, Zuo B, Li KK, Lam TC | display-authors=etal| title=Proteomic analysis of chick retina during early recovery from lens‑induced myopia. | journal=Mol Med Rep | year= 2018 | volume= 18 | issue= 1 | pages= 59-66 | pmid=29749514 | doi=10.3892/mmr.2018.8954 | pmc=6059693 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=29749514 }} </ref> | |||
<ref>{{Cite journal |last=Tarutta |first=Elena |date=2016 |title=Long -term effects of optical defocus on eye growth and refractogenesis |url=https://www.pum.edu.pl/__data/assets/pdf_file/0007/112849/PomeranianJLifeSci_62-01_025-030.pdf |journal=Pomeranian J Life Sci}}</ref><ref>{{Cite journal |last=Zhu |first=Xiaoying |last2=McBrien |first2=Neville A. |last3=Smith |first3=Earl L. |last4=Troilo |first4=David |last5=Wallman |first5=Josh |date=2013-04-01 |title=Eyes in Various Species Can Shorten to Compensate for Myopic Defocus |url=https://iovs.arvojournals.org/article.aspx?articleid=2189093 |journal=Investigative Ophthalmology & Visual Science |language=en |volume=54 |issue=4 |pages=2634–2644 |doi=10.1167/iovs.12-10514 |issn=1552-5783}}</ref> | <ref>{{Cite journal |last=Tarutta |first=Elena |date=2016 |title=Long -term effects of optical defocus on eye growth and refractogenesis |url=https://www.pum.edu.pl/__data/assets/pdf_file/0007/112849/PomeranianJLifeSci_62-01_025-030.pdf |journal=Pomeranian J Life Sci}}</ref><ref>{{Cite journal |last=Zhu |first=Xiaoying |last2=McBrien |first2=Neville A. |last3=Smith |first3=Earl L. |last4=Troilo |first4=David |last5=Wallman |first5=Josh |date=2013-04-01 |title=Eyes in Various Species Can Shorten to Compensate for Myopic Defocus |url=https://iovs.arvojournals.org/article.aspx?articleid=2189093 |journal=Investigative Ophthalmology & Visual Science |language=en |volume=54 |issue=4 |pages=2634–2644 |doi=10.1167/iovs.12-10514 |issn=1552-5783}}</ref> | ||
Revision as of 20:26, 4 June 2020
What is Blur
There are many sources of failure to recognize characters, blur is the only one addressed by EM. Blur is when the edges of the thing you are looking at is not well defined. Print may be too small to see without being blurry. A normal healthy eye can experience blur by looking through a lens not designed for it.
Myopic vs Hyperopic Blur
Myopic blur is the type of blur normally experienced by people with uncompensated myopia. Hyperopic blur is the type normally experienced by people with uncompensated hyperopia. In order to induce blur, use a lens with the opposite diopter sign as the lens normally used for blur correction, so a plus lens will give myopic blur to an emmetrope. A weak negative lens will give myopic blur to a myope.
Diffusion blur
Diffusion such as frosted glass, causes myopia just as strong myopic lenses do in growing animals. This is also called form deprivation.
Directional blur
Text appears smeared in a direction. This is the defining symptom of astigmatism
Defocus as a stimulus for eye length changes
The eye needs stimulus to make corrective changes. Studies have shown that inducing defocus can induce axial lengthening and shortening. [1] [2][3]
EM Blur Adaption
"Blur Adaption" unfortunately has two meanings. The meaning commonly meant by EM forum members is encountering so much blur that your eye no longer tried to accommodate the blur. This is something like learned helplessness at the biological level.
Clinical Blur Adaption
When a doctor uses the term "Blur Adaption" they mean that a person has adapted to perform visual tasks despite their blur. This is almost the opposite of EM blur adaption.
See Also
External sources
https://www.sciencedirect.com/science/article/pii/S0042698906005621 - Conceptual model of human blur perception
References
- ↑ Zhou YY, Chun RKM, Wang JC, Zuo B, Li KK, Lam TC; et al. (2018). "Proteomic analysis of chick retina during early recovery from lens‑induced myopia". Mol Med Rep. 18 (1): 59–66. doi:10.3892/mmr.2018.8954. PMC 6059693. PMID 29749514.CS1 maint: multiple names: authors list (link)Page Module:Citation/CS1/styles.css has no content.
- ↑ Tarutta, Elena (2016). "Long -term effects of optical defocus on eye growth and refractogenesis" (PDF). Pomeranian J Life Sci.Page Module:Citation/CS1/styles.css has no content.
- ↑ Zhu, Xiaoying; McBrien, Neville A.; Smith, Earl L.; Troilo, David; Wallman, Josh (2013-04-01). "Eyes in Various Species Can Shorten to Compensate for Myopic Defocus". Investigative Ophthalmology & Visual Science. 54 (4): 2634–2644. doi:10.1167/iovs.12-10514. ISSN 1552-5783.Page Module:Citation/CS1/styles.css has no content.