The influence of near-work on development of myopia among university students. A three-year longitudinal study among engineering students in Norway.

PURPOSE: The aim of this study was to investigate the effect of near-work on development and progression of myopia among adults exposed to high educational demands. METHODS: A three-year longitudinal refraction study was performed among 224 Norwegian engineering students (mean age 20.6 years, 117 females and 107 males) measuring their refraction at the beginning and the end of the period. The examinations included automated and clinical refraction in cycloplegia and a questionnaire regarding time spent on different kinds of near-work was filled in by the participants. A total of 192 students (100 females and 92 males) completed the study. RESULTS: The mean refractive change of -0.51+/-0.49 D (n=192) during the three-year period was statistically significant (p=0.0001). A significant relationship between refractive change towards myopia and time spent on reading scientific literature (p< or =0.001) and on practical near-work (p< or =0.05), respectively, was found. Also, a significant relationship between refractive change towards myopia and time spent at lectures was revealed (p< or =0.001). No relationship was found between refractive change and time spent at working with video display terminals (VDT) or watching television, respectively. CONCLUSIONS: The results indicate that intensive near-work could initiate myopia or lead to its progression in young adults. The time spent on near-work seems to play a significant role in that process.

Biometric changes in the eyes of Norwegian university students--a three-year longitudinal study.

PURPOSE: The aim of this study was to investigate the changes in biometric measurements and corresponding refractive errors during a three-year period among university students exposed to high educational demands. METHODS: A three-year longitudinal cohort study was performed among 149 Norwegian engineering students (79 females and 70 males, mean age 20.6+/-1.2 years) measuring their refraction and ocular dimensions at the beginning and at the end of the period. The examinations included refraction, keratometry, and A-scan ultrasonographic measurements of the ocular components, all made in cycloplegia. RESULTS: After three years the mean refractive change was -0.52+/-0.45 D (p<0.05), which was accompanied by a change in lens thickness of 0.07+/-0.10 mm (p<0.05), and a vitreous chamber elongation of 0.27+/-0.30 mm (p<0.05). The results refer to the right eye. Stratification of the sample based on their initial refraction (myopes, emmetropes, and hyperopes) showed refractive change towards myopia for all subgroups as well as a significant increase in lens thickness and vitreous chamber depth. No significant three-year change in anterior chamber depth or corneal curvature was found in any of the groups. For all groups, vitreous chamber elongation gave a notable dioptric change in myopic direction. CONCLUSIONS: A shift in refraction towards myopia after puberty is accompanied by vitreous chamber elongation which can explain the dioptric change in myopic direction.