Siemens biography 16 specsavers

The prevalence of uncorrected refractiveerrors in underserved rural areas.

PubMed

Hashemi, Hassan; Abbastabar, Hedayat; Yekta, Abbasali; Heydarian, Samira; Khabazkhoob, Mehdi

2017-12-01

To determine the prevalence of uncorrected refractiveerrors, need for spectacles, and the determinants of unmet need in underserved rural areas of Iran. In a cross-sectional study, multistage cluster sampling was done in 2 underserved rural areas of Iran. Then, all subjects underwent vision testing and ophthalmic examinations including the measurement of uncorrected visual acuity (UCVA), best corrected visual acuity, visual acuity with current spectacles, auto-refraction, retinoscopy, and subjective refraction. Need for spectacles was defined as UCVA worse than 20/40 in the better eye that could be corrected to better than 20/40 with suitable spectacles. Of the 3851 selected individuals, 3314 participated in the study. Among participants, 18.94% [95% confidence intervals (CI): 13.48-24.39] needed spectacles and 11.23% (95% CI: 7.57-14.89) had an unmet need. The prevalence of need for spectacles was 46.8% and 23.8% in myopic and hyperopic participants, respectively. The prevalence of unmet need was 27% in myopic, 15.8% in hyperopic, and 25.46% in astigmatic participants. Multiple logistic regression showed that education and type of refractiveerrors were associated with uncorrected refractiveerrors; the odds of uncorrected refractiveerrors were highest in illiterate participants, and the odds of unmet need were 12.13, 5.1, and 4.92 times higher in myopic, hyperopic and astigmatic participants as compared with emmetropic individuals. The prevalence of uncorrected refractiveerrors was rather high in our study. Since rural areas have less access to health care facilities, special attention to the correction of refractiveerrors in these areas, especially with inexpensive methods like spectacles, can prevent a major proportion of visual impairment.

Prevalence of refractiveerrors

Why Sketching May Aid Learning From Science Texts: Contrasting Sketching With Written Explanations.

PubMed

Scheiter, Katharina; Schleinschok, Katrin; Ainsworth, Shaaron

2017-10-01

The goal of this study was to explore two accounts for why sketching during learning from text is helpful: (1) sketching acts like other constructive strategies such as self-explanation because it helps learners to identify relevant information and generate inferences; or (2) that in addition to these general effects, sketching has more specific benefits due to the pictorial representation that is constructed. Seventy-three seventh-graders (32 girls, M = 12.82 years) were first taught how to either create sketches or self-explain while studying science texts. During a subsequent learning phase, all students were asked to read an expository text about the greenhouse effect. Finally, they were asked to write down everything they remembered and then answer transfer questions. Strategy quality during learning was assessed as the number of key concepts that had either been sketched or mentioned in the self-explanations. The results showed that at an overall performance level there were only marginal group differences. However, a more in-depth analysis revealed that whereas no group differences emerged for students implementing either strategy poorly, the sketching group clearly outperformed the self-explanation group for students who applied the strategies with higher quality. Furthermore, higher sketching quality was strongly related to better learning outcomes. Thus, the study's results are more in line with the second account: Sketching can have a beneficial effect on learning above and beyond generating written explanations; at least, if well deployed. Copyright © 2017 Cognitive Science Society, Inc.

User's Guide for SKETCH

NASA Technical Reports Server (NTRS)

Hedgley, David R., Jr.

2000-01-01

A user's guide for the computer program SKETCH is presented on this disk. SKETCH so