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Background The near work and outdoor activity are the most important environmental risk factors for myopia. However, data from Chinese rural children are relatively rare and remain controversial. Therefore, the purpose of this study was to evaluate the relationship of both near work and outdoor activities with refractive error in rural children in China. Methods In this cross-sectional study, 572 (65.1%) of 878 children (6–18 years of age) were included from the Handan Offspring Myopia Study (HOMS). Information from the parents on these children, as well as the parent’s non-cycloplegic refraction, were obtained from the database of the Handan Eye Study conducted in the years 2006–2007. A comprehensive vision examination, including cycloplegic refraction, and a related questionnaire, were assessed on all children. Results The overall time spent on near work and outdoor activity in the children was 4.8 ± 1.6 and 2.9 ± 1.4 h per day, respectively. Myopic children spent more time on near work (5.0 ± 1.7 h vs.4.7 ± 1.6 h, p = 0.049), while no significant difference was found in outdoor activity hours (2.8 ± 1.3 h vs. 3.0 ± 1.4 h, p = 0.38), as compared to non-myopic children. In the multiple logistic analysis, in general, no association between near work and myopia was found after adjusting for the children’s age, gender, parental refractive error, parental educational level, and daily outdoor activity hours [odds ratio (OR), 95% confidence interval (CI): 1.10, 0.94–1.27]. However, a weak protective effect of the outdoor activity on myopia was found (OR, 95% CI: 0.82, 0.70–0.96), after adjusting for similar confounders. Conclusions In general, no association between near work and myopia was found, except for the high near work subgroup with moderate outdoor activity levels. A weak protective effect of outdoor activity on myopia in Chinese rural children was observed. Electronic supplementary material The online version of this article (10.1186/s12886-017-0598-9) contains supplementary material, which is available to authorized users.

Background To describe the prevalence and associations of posterior vitreous detachment (PVD) in a rural adult Chinese population. Methods All eligible subjects were requested to carry out a comprehensive eye examination; PVD was a pre-specified outcome variable and was determined via biomicroscopical examination (slit-lamp biomicroscopy) with a +90-D preset lens after mydriasis. Prevalence was standardized to China population census (2000). Results 5890 (86.2%) subjects completed the examination of slit-lamp biomicroscopy with a +90-D lens. PVD was present in 160 participants (2.7%); the standardized prevalence was 2.0% (95% confidence interval [CI], 1.6-2.3%). PVD developed increasingly with age (P for trend Conclusions About one in fifty people is found to have PVD in this population-based study. Age and female are independently associated with PVD occurrence.

Background To date, studies on the role played by cigarette smoking in primary open-angle glaucoma (POAG) remains controversial. The current study evaluated cigarette smoking as a risk factor of POAG and its relationships with vertical cup-to-disc ratio (VCDR), central corneal thickness (CCT) and intraocular pressure (IOP) in a Chinese cohort. Methods In a total of 248 unrelated individuals including 30 juvenile-onset POAG (JOAG), 92 adult-onset POAG (AOAG) and 126 sex-matched senile cataract controls, underwent comprehensive ophthalmic examination. Their smoking was obtained and documented by questionnaire. Association of cigarette smoking with POAG was performed using logistic regression controlled for age and sex. Effects of cigarette smoking on VCDR, IOP and CCT were analyzed with multiple linear regression. Results In either JOAG or AOAG, no association of cigarette smoking was found with disease onset (P = 0.692 and 0.925 respectively). In controls and JOAG, no significant effects of smoking were found on VCDR, IOP or CCT (all P > 0.05). Smoking was found to be correlated with decreased CCT in AOAG and combined POAG (JOAG + AOAG) (P = 0.009 and 0.003), but no association with VCDR or IOP was observed (P > 0.05). Conclusions Although cigarette smoking was not found to be risk factor for onset of POAG, it was correlated with CCT in AOAG, and thus might still play a role in the disease course, especially for AOAG.