Review of school vision screening guidelines

Abstract: Background: Vision screenings are important in identifying visual anomalies likely to disrupt the physical, intellectual, social and emotional development of children. School health services globally include vision screenings, complementing a variety of associated screening services. Aim: This review article provides evidence for content, provision and efficacy of the vision screening services for children of school-going age and reports on the current practice of children’s vision screenings worldwide including in South Africa. Methods: Studies were identified from PubMed, Ebscohost and Science Direct with the search terms utilised during the selection of electronic articles and journals for the review. The target population includes children of school-going age from 6 to 19 years without previously known conditions associated with visual anomalies and learning-related problems. The quality of vision screening programmes and policies for the school-going age children in different countries were evaluated using Wilson and Jungner criteria.1 Results: Vision screening programmes worldwide appear to support comprehensive vision screening methods among pre-schoolers (from birth to ≤ 6 years vs. children of school-going age). The development of vision screening procedures in some countries in the United States of America (USA) was found to be grounded on epidemiologic findings and principles. These may have contributed towards the formulation of national vision screening guidelines for preschoolers that supported the detection of amblyopia and its associated conditions such as strabismus, anisometropia and myopia. School-going children’s vision screenings are not supported worldwide as research has shown that there is lack of benefits for detecting other visual anomalies such as vergence and accommodative dysfunctions. This is despite evidence provided by the literature reviewed that an association exists between prevalent accommodation and vergence dysfunctions including poor ocular motilities and poor near-vision, among children of school-going age with poor academic performance. Conclusion: The guidelines worldwide support school vision screenings, especially for the pre-schoolers by the school health nurses, with other programs having considered the teachers, optometrists or orthoptists as the appropriate personnel to conduct the school vision screenings. There is still a need for the effectiveness of the school vision-screening programmes to be investigated related to the importance of detecting convergence and accommodative dysfunctions for the school going age children

Health effects and wind turbines: A review of the literature

<p>Abstract</p> <p>Background</p> <p>Wind power has been harnessed as a source of power around the world. Debate is ongoing with respect to the relationship between reported health effects and wind turbines, specifically in terms of audible and inaudible noise. As a result, minimum setback distances have been established world-wide to reduce or avoid potential complaints from, or potential effects to, people living in proximity to wind turbines. People interested in this debate turn to two sources of information to make informed decisions: scientific peer-reviewed studies published in scientific journals and the popular literature and internet.</p> <p>Methods</p> <p>The purpose of this paper is to review the peer-reviewed scientific literature, government agency reports, and the most prominent information found in the popular literature. Combinations of key words were entered into the Thomson Reuters Web of Knowledge^SMand the internet search engine Google. The review was conducted in the spirit of the evaluation process outlined in the Cochrane Handbook for Systematic Reviews of Interventions.</p> <p>Results</p> <p>Conclusions of the peer reviewed literature differ in some ways from those in the popular literature. In peer reviewed studies, wind turbine annoyance has been statistically associated with wind turbine noise, but found to be more strongly related to visual impact, attitude to wind turbines and sensitivity to noise. To date, no peer reviewed articles demonstrate a direct causal link between people living in proximity to modern wind turbines, the noise they emit and resulting physiological health effects. If anything, reported health effects are likely attributed to a number of environmental stressors that result in an annoyed/stressed state in a segment of the population. In the popular literature, self-reported health outcomes are related to distance from turbines and the claim is made that infrasound is the causative factor for the reported effects, even though sound pressure levels are not measured.</p> <p>Conclusions</p> <p>What both types of studies have in common is the conclusion that wind turbines can be a source of annoyance for some people. The difference between both types is the reason for annoyance. While it is acknowledged that noise from wind turbines can be annoying to some and associated with some reported health effects (e.g., sleep disturbance), especially when found at sound pressure levels greater than 40 db(A), given that annoyance appears to be more strongly related to visual cues and attitude than to noise itself, self reported health effects of people living near wind turbines are more likely attributed to physical manifestation from an annoyed state than from wind turbines themselves. In other words, it appears that it is the change in the environment that is associated with reported health effects and not a turbine-specific variable like audible noise or infrasound. Regardless of its cause, a certain level of annoyance in a population can be expected (as with any number of projects that change the local environment) and the acceptable level is a policy decision to be made by elected officials and their government representatives where the benefits of wind power are weighted against their cons. Assessing the effects of wind turbines on human health is an emerging field and conducting further research into the effects of wind turbines (and environmental changes) on human health, emotional and physical, is warranted.</p

Alleviating health risks associated with rainwater harvesting

Perceived and real public health risks associated with the quality of water from alternative water sources and supply systems, such as rainwater harvesting (RWH) and grey water reuse, continue to restrict their uptake in many countries. One option to alleviate these health risks is to treat alternative water to potable standard at the point of use (POU) as opposed to the point of supply, as undertaken in centralised systems. This paper presents the results of three international empirical field trials of a novel POU RWH treatment device. The results indicate that where the harvested rainwater did not contain elevated levels of pesticides or physico-chemical determinands, the POU device was able to reduce levels in outlet water to meet UK, EU and World Health Organization potable standards. Regarding microbiological determinands, such as total viable counts and coliforms, and microbial pathogens, such as Pseudomonas aeruginosa and Legionella spp., the device achieved reduction to potable standard and full pathogen removal, respectively. Thus, while it is possible to treat harvested rainwater to potable standard with a POU device, whether it is desirable to do so to alleviate risks for all end uses remains a question for further debate

Library notes and news /

Title from caption.Mode of access: Internet.Vols. for 1905-June 1919 issued by the Minnesota Public Library Commission; Sept. 1919-June 1937 by the Library Division of the Dept. of Education.1931-33 in v. 10.Continued in Sept. 1937 by: Minnesota library notes and news

The reaction of swamp forests to drainage in northern Minnesota /

Bureau of public roads, United States Department of agriculture, Lake states forest experiment station, Forest service, U.S. Department of agriculture, cooperating. E. V. Willard, commissioner of drainage and waters, state of Minnesota, in administrative charge of investigations.Department of drainage and waters, state of Minnesota, Department of forestry and fire prevention, state of Minnesota, Division of forestry, University of Minnesota, Division of agricultural engineering, University of Minnesota.Mode of access: Internet