AZAR eye and vision cohort study.

According to World Health Organization (WHO), currently, 2.2 billion people are living with visual impairment worldwide, of which almost half could have been prevented. There are both modifiable and unmodifiable factors leading to visual disability and, ultimately, blindness. Several population-based studies in different parts of Iran have tried to determine these factors concerning their specific population and environment-related characteristics. AZAR Eye and Vision cohort is the second-largest cohort study in the whole country. AZAR Eye and Vision cohort is the ophthalmologic branch of AZAR cohort which is the largest eye cohort study in the country, which is trying to determine the prevalence and incidence of visual impairment, blindness, and other major ophthalmologic conditions and their associated risk factors in East Azerbaijan province located in Iran, a middle eastern country. A recently emerging phenomenon is the drying of the ultra-salty lake of Urmia located in the West Azerbaijan province which is a direct neighbor of our studied population and has caused recurrent salt storms in the immediate near areas. This phenomenon could adversely affect visual health via different conditions which our study will elucidate. The enrollment phase took place between 2014 and 2017 and 11,208 participants were enrolled out of 15,000 participants in the primary cohort. The resurvey phase will begin five years after the enrollment phase. In this phase, 30% of the participants are randomly selected to be reexamined and complete questionnaires. The participants showing any issues such as diabetes and being a glaucoma suspect will be included in the resurvey phase, too. Data categories gathered include demographics, lifestyle factors, past medical and drug histories, and a diet quality and quantity questionnaire including 130 edible items. Urine, hair, nail, and 25-ml blood samples, were collected from the participants. Then they were referred to an optometrist to complete an ophthalmologic questionnaire and undergo eye examination and lensometry. Then they underwent slit-lamp examinations and pictures were taken of the lens and fundus. People with suspected visual impairment were referred to an ophthalmology clinic. The data are processed and a four-level quality check is performed on each block. The most common visual impairment is cataracts. This study's most important aim is to evaluate the effect of local environmental and ethnic factors on eye diseases in this specific population.