Purpose: To investigate the visual acuity of preschoolers aged 3 to 6 years in Shenzhen of China. Methods:Visual acuity was measured in preschoolers from eight kindergartens in Shenzhen. Results:A total of 1147 childr...Purpose: To investigate the visual acuity of preschoolers aged 3 to 6 years in Shenzhen of China. Methods:Visual acuity was measured in preschoolers from eight kindergartens in Shenzhen. Results:A total of 1147 children completed the visual acuity test.There were 77 boys and 62 girls aged 3 years,259 and 216 aged 4,193 and 160 aged 5 and 94 and 86 aged 6. The mean visual acuities of children aged 3,4,5,and 6 years were 0.51±0.10, 0.54±0.13, 0.65±0.14, and 0.71±0.17, respectively. The visual acuity was significantly improved with increasing age (P=0.000). Conclusion:For preschoolers aged 3 to 6, the visual acuity continuously develops and improves. Therefore, age should be considered when diagnosing amblyopia in children.展开更多
The objective of this paper is to evaluate the Vialit Adhesion Test and its potential for use within performance oriented specifications for seal treatments. Multiple aggregates and emulsions are evaluated with existi...The objective of this paper is to evaluate the Vialit Adhesion Test and its potential for use within performance oriented specifications for seal treatments. Multiple aggregates and emulsions are evaluated with existing test methods and with modified equipment and methods. The results indicate the current test tray is inadequate and that a thicker tray provides better results. Conditioning that incorporated either freeze times between 4 to 8 hours and/or freeze thaw cycles were also found to be improvements to the current conditioning methods. The specified mass of the steel spheres used during the test may be too restrictive in that more economical spheres were tested and did not show differences in aggregate loss.展开更多
文摘Purpose: To investigate the visual acuity of preschoolers aged 3 to 6 years in Shenzhen of China. Methods:Visual acuity was measured in preschoolers from eight kindergartens in Shenzhen. Results:A total of 1147 children completed the visual acuity test.There were 77 boys and 62 girls aged 3 years,259 and 216 aged 4,193 and 160 aged 5 and 94 and 86 aged 6. The mean visual acuities of children aged 3,4,5,and 6 years were 0.51±0.10, 0.54±0.13, 0.65±0.14, and 0.71±0.17, respectively. The visual acuity was significantly improved with increasing age (P=0.000). Conclusion:For preschoolers aged 3 to 6, the visual acuity continuously develops and improves. Therefore, age should be considered when diagnosing amblyopia in children.
文摘The objective of this paper is to evaluate the Vialit Adhesion Test and its potential for use within performance oriented specifications for seal treatments. Multiple aggregates and emulsions are evaluated with existing test methods and with modified equipment and methods. The results indicate the current test tray is inadequate and that a thicker tray provides better results. Conditioning that incorporated either freeze times between 4 to 8 hours and/or freeze thaw cycles were also found to be improvements to the current conditioning methods. The specified mass of the steel spheres used during the test may be too restrictive in that more economical spheres were tested and did not show differences in aggregate loss.
