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National and sub-national burden of visual impairment in Iran 1990-2013; study protocol.

BACKGROUND
Although Visual impairment (VI) and its prevention is a public health issue, sub-optimal information about its magnitude in national level and its distribution is one of the impediments for visual health advocacy. In this article, we are detailing the approaches which will be taken to estimate the magnitude (prevalence, incidence, and burden), distribution, and trend (1990 to 2013) of low vision and blindness in Iran. Besides that, an attempt will be made to describe inequalities and their determinants.


METHODS
After finalizing the list of diseases, a systematic search will be started using confirmed search terms and all published and unpublished data will be extracted. Other data sources, including data from hospital records will be added to the data extraction sheet. Using distinct statistical models including spatio-temporal model and multilevel autoregressive model, we will estimate rate of burden measures of eye disease and their uncertainty interval by sex, age, year, and province as well as social determinants of visual impairment inequality. The results are to be reported in separated analyses of meta-analysis, trend, risk factors and diseases burden, inequality, Bayesian prediction modeling, and map for visualizing the results.


CONCLUSION
The results of the current study will address gaps in different regions and have implication for evidence-based policy making in Iran.