However, the currently identified variants account for only a small fraction of myopia cases, suggesting the existence of a large number of yet unidentified low-frequency or small-effect variants, which underlie the majority of myopia cases. Environmental factors
Environmental factors which increase the risk of nearsightedness include insufficient light exposure, low physical activity, near work, and increased year of education.One hypothesis is that a lack of normal visual stimuli causes improper development of the eyeball. Under this hypothesis, "normal" refers to the environmental stimuli that the eyeball evolved to. Modern humans who spend most of their time indoors, in dimly or fluorescently lit buildings may be at risk of development of myopia.People, and children especially, who spend more time doing physical exercise and outdoor play have lower rates of myopia, suggesting the increased magnitude and complexity of the visual stimuli encountered during these types of activities decrease myopic progression. There is preliminary evidence that the protective effect of outdoor activities on the development of myopia is due, at least in part, to the effect of long hours of exposure to daylight on the production and the release of retinal dopamine.Myopia can be induced with minus spherical lenses, and overminus in prescription lenses can induce myopia progression. Overminus during refraction can be avoided through various techniques and tests, such as fogging, plus to blur, and the duochrome test.The near work hypothesis, also referred to as the "use-abuse theory" states that spending time involved in near work strains the intraocular and extraocular muscles.
For optimal use, if used as a suppository, it is recommended that bisacodyl be given after breakfast to synchronize with the gastrocolic reflex. Two suppositories can be inserted at once if a very strong, purgative, enema-like result is needed. A few hours after the initial evacuation, there can be a secondary action which will continue as long as there is unexpelled bisacodyl present in the rectum. As a commercially prepared micro-enema, it is usually effective in 5 to 20 minutes. Mechanism of action
Bisacodyl works by stimulating enteric neurons to cause peristalsis, i.e., colonic contractions. It is also a contact laxative; it increases fluid and salt secretion. The action of bisacodyl on the small intestine is negligible; stimulant laxatives mainly promote evacuation of the colon. See also
Diphenyl-2-pyridylmethane
Cyclofenil

References
External links
|Bisacodyl,00.html Bisacodyl at Drugdigest.org
Bisacodyl Consumer Drug Information
Dulcolax Laxative
Dulcoflex Tablet Uses in Hindi