HOMEPRODUCTSCOMPANYCONTACTFAQResearchDictionaryPharmaSign Up FREE or Login

Time outdoors and the prevention of myopia.

Abstract
Recent epidemiological evidence suggests that children who spend more time outdoors are less likely to be, or to become myopic, irrespective of how much near work they do, or whether their parents are myopic. It is currently uncertain if time outdoors also blocks progression of myopia. It has been suggested that the mechanism of the protective effect of time outdoors involves light-stimulated release of dopamine from the retina, since increased dopamine release appears to inhibit increased axial elongation, which is the structural basis of myopia. This hypothesis has been supported by animal experiments which have replicated the protective effects of bright light against the development of myopia under laboratory conditions, and have shown that the effect is, at least in part, mediated by dopamine, since the D2-dopamine antagonist spiperone reduces the protective effect. There are some inconsistencies in the evidence, most notably the limited inhibition by bright light under laboratory conditions of lens-induced myopia in monkeys, but other proposed mechanisms possibly associated with time outdoors such as relaxed accommodation, more uniform dioptric space, increased pupil constriction, exposure to UV light, changes in the spectral composition of visible light, or increased physical activity have little epidemiological or experimental support. Irrespective of the mechanisms involved, clinical trials are now underway to reduce the development of myopia in children by increasing the amount of time they spend outdoors. These trials would benefit from more precise definition of thresholds for protection in terms of intensity and duration of light exposures. These can be investigated in animal experiments in appropriate models, and can also be determined in epidemiological studies, although more precise measurement of exposures than those currently provided by questionnaires is desirable.
AuthorsAmanda N French, Regan S Ashby, Ian G Morgan, Kathryn A Rose
JournalExperimental eye research (Exp Eye Res) Vol. 114 Pg. 58-68 (Sep 2013) ISSN: 1096-0007 [Electronic] England
PMID23644222 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Review)
CopyrightCopyright © 2013 Elsevier Ltd. All rights reserved.
Chemical References
  • Dopamine
Topics
  • Accommodation, Ocular
  • Animals
  • Dopamine (metabolism)
  • Environmental Exposure
  • Eye (growth & development, metabolism)
  • Humans
  • Light
  • Myopia (prevention & control)
  • Time Factors

Join CureHunter, for free Research Interface BASIC access!

Take advantage of free CureHunter research engine access to explore the best drug and treatment options for any disease. Find out why thousands of doctors, pharma researchers and patient activists around the world use CureHunter every day.
Realize the full power of the drug-disease research graph!


Choose Username:
Email:
Password:
Verify Password:
Enter Code Shown: