No abstract

An association between physical activity and myopia was observed, suggesting a protective effect of physical activity on the development and progression of myopia in university students. The results confirm that intensive studying is a risk factor of myopia and that myopic progression or development is more likely in medical students in their early 20s than in their late 20s.

Hong Kong Chinese students had a higher prevalence of myopia regardless of whether they studied in local or international schools when compared with other ethnic groups, such as whites. This further supports a genetic input into myopia development.

This review aims at elucidating the interaction between genetic and environmental factors in the aetiology of primarily low myopia. Genetics greatly influence the growth of the eye, but the fine correlation between the components of refraction for the eye to become emmetrope is affected by environmental factors such as education, metabolism, physical activity, and outdoor activity.

ABSTRACT.Purpose: This study aimed to determine the prevalence of myopia among Danish conscripts and compare the results with those from similar Danish studies carried out in 1882 and 1964. Furthermore, the relationships between myopia and educational level, ethnicity, intelligence (IQ), body mass index (BMI) and height were analysed. Methods: We carried out a cross-sectional study based on medical reports for 4681 male conscripts. The following data were collected from September to December 2004: age; place of birth; weight; height; power of spectacles or contact lenses; visual acuity; number of years at school (8-13 years); occupation; intelligence test (IQ test) score, and ethnicity. The prevalence of high myopia has decreased significantly since 1882 and has also tended to decrease from 1964. Number of years in education and IQ test score were related to myopia.

The prevalence of myopia among Danish children was 17.9%. By logistic regression and slope analysis, we found no association between PA and myopia, in this first of its kind study based on objective and repeated PA data.

ABSTRACT.Published data from all parts of the world show that myopia is rare before school age, gradually increases during school life and reaches its highest level of prevalence during the years of most intense study at university. It is widely held that continuous reading harms the eyes, but none of the attempts made so far to reduce accommodative fatigue by introducing pauses during reading and teaching, eye exercises, etc. have been successful in reducing the number of children who develop myopia. However, we should not exclude the possibility that the introduction into schools of better tables, better lighting, more breaks and more sport has not only benefited the general health of children, mentally as well as physically, but has also decreased the development and progression of myopia. More research in this area is needed, but relevant protocols are difficult to establish. The aetiology of myopia is multifactorial and both genes and environment play important roles. Twin studies indicate a strong genetic influence and a weak environmental impact, while extreme myopia prevalences among selected population groups (university students) point to the opposite.

ABSTRACT.Purpose: To present and discuss oculometry data in a series of adults with high myopia followed between the ages of 26 and 54 years. Emphasis is on axial length (AL) findings and corneal curvature radius (Crad).Methods: Thirty-four out of the 39 individuals recruited as teenagers from a Copenhagen 1948 birth cohort with myopia of at least 6 D have had current follow-up exams, to include AL measurements (by ultrasound, 1974-2002; the latter year also with the Zeiss IOLMaster) and keratometry. The cross-sectional and longitudinal analyses are based primarily on the eyes with high myopia; however, the fellow eye is also assessed in unilateral cases.Results: At age 54 years, the maximum myopia in the series was )26 D; the highest AL value was 35.4 mm. The myopia had increased in most, with an increase from the 26-year oculometry baseline averaging 1.0 D [standard deviation (SD) 1.84]. Ultrasound measurements over the 28 years gave a significant correlation between axial eye elongation and myopia progression of adult age (r = 0.65). The regression line was y = 0.43 + 0.36x, with myopia increase on the x-axis. Throughout sessions, the association between AL and refraction was given by correlation coefficients numerically above 0.8, whereas AL and Crad had r-values of 0.3-0.5. However, a mean Crad in the sample of 7.66 (SD 0.28) mm meant that the more general expectancy of rather flat corneas in high myopia was not fulfilled. Our data further suggested a reduction in lens power over the study period. Conclusion:In relation to refraction, AL and Crad remain the two main oculometry parameters. Apparently the correlation patterns regarding the cornea that are broadly valid for axial ametropia in the population cannot be extended to the marginal high myopia tail of the distribution. A significant proportion of eyes with high myopia thus had steeper corneas than expected, as a so-called index contribution (albeit a small one) to the marginal refractive error.Key words: adult age follow-up -corneal steepness in high myopia -high myopia -IOLMaster eye length measurement -keratometry -lens power calculation -ultrasound oculometry