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

Prevalence and Burden of Refractive Errors at National and Sub-national Levels in Iran

Purpose

To estimate the prevalence, burden of refractive errors and their associated trend from 1990 to 2018 and geographic inequalities in Iran.

Methods

Data regarding the epidemiology of refractive errors was extracted from three different sources: systematic review of published literature, data from visual school screening programs, and data from Iran's national health survey (NHS). The pool of all available data on refractive errors as well as demographic, location, and socioeconomic status covariates were fitted in spatio-temporal and Gaussian process regression models to predict the prevalence of refractive errors from the years 1990 to 2018 in 31 provinces grouped by age and sex in order to calculate years lived with disability (YLDs).

Results

In 2018, the age-adjusted prevalence of refractive errors was 16.32% (95% uncertainty interval [UI]: 12.44-21.48%) in both sexes, 17.98% (95% UI: 13.74-23.61%) in women, and 14.66% (95% UI: 11.14-19.36%) in men. The prevalence of refractive errors reveals that it increases with age. Refractive errors contributed to 441.41 and 348.38 YLDs in men and women, respectively. The age-standardized prevalence growth was 31.30% in females and 24.32% in males from the years 1990 to 2018. Significant geographical heterogeneity was observed. The age-standardized YLDs rates of refractive errors represent an increasing trend of 28.9% increase from 1990 to 2018.

Conclusion

Over 28 years, the prevalence of refractive errors increased significantly. Women tend to have higher rates of prevalence. The prevalence increased in older ages. Border provinces had the lowest prevalence. Age-standardized YLDs rates of refractive errors increased by about 30%.

Spatio-Temporal Analysis of the Hepatitis B Prevalence in Iranian Blood Donors from 2000 to 2016 at National and Provincial Level

BACKGROUND

High risk blood transfusions can cause a lot of financial and psychological burden to the community. The prevalence of Hepatitis B is useful for evaluating the blood products' safety and donor selection methods. We aimed to predict the prevalence of hepatitis B in Iranian blood donors from 2000-2016.

METHODS

Positive cases of hepatitis B from 2006 to 2014 were collected from Iranian Blood Transfusion Organization. This database was classified according to the age, provinces, and type of donation. Data was not existed in all subnational levels and all years, therefore, for predicting the hepatitis B prevalence, two separate, Spatio-temporal and mixed model (GLMM) were developed.

RESULTS

At the national level, the hepatitis B prevalence declined from 0.69 (0.51 to 0.90) in 2000 to 0.27 (0.21 to 0.33) in 2016. In first-time, regular, and repeated donors, this prevalence declined from 2.31 (1.74 to 2.31), 0.26 (0.19 to 0.34), and 0.51 (0.38 to 0.68) in 2000 to 0.87 (0.69 to 1.09), 0.09 (0.07 to 0.12), and 0.19 (0.14 to 0.24) in 2016. At the provincial level, the highest and lowest prevalence in 2016 was observed in North Khorasan and Gilan. With increasing age, the average prevalence of hepatitis B, increased.

CONCLUSION

Prevalence of hepatitis B in Iranian blood donors has been reduced significantly over 17 years, but still new cases of hepatitis B are reported. By precise monitoring the donor selection process and implementing more sensitive laboratory screening, we can reduce the risk of new infectious agents.

Visual Impairment Prevalence, Causes, and Role of Healthcare Access: A Systematic Review and Meta-Analysis in Iran

Purpose

Healthcare access is one of the determinants of visual impairment (VI), as a public health problem. The objective of this study was to estimate VI prevalence, related causes, and its correlation with access to physicians in Iran.

Methods

: This systematic review and meta-analysis include observational studies published in Iran. PubMed, Web of Science, Scopus, Google Scholar, and local databases were systematically searched by using the MeSH headings. Data on the provincial distribution of physicians, as an index of access to healthcare, was retrieved. A random-effect meta-analysis was performed to assess.

Results

Eight articles were included. The pooled prevalence of blindness, low vision, and VI was 0.80% (95% CI: 0.61–0.99%), 2.92% (95% CI: 2.40–3.44%), and 5.57% (95% CI: 4.71–6.43%). Refractive errors were the most common causes of VI based on PVA with the pooled prevalence of 54.6% (95% CI: 43.4–65.8%). Based on BCVA, we found that the pooled prevalence of cataracts was 37.4% (95% CI: 29.5–45.3%) as the most common cause of VI. The results of metaregression showed that the greater number of general practitioners (GPs) (P value = 0.01) and pharmacists (P value = 0.024) per population were associated with a lower prevalence of blindness.

Conclusion

Some of the main causes of visual impairment in Iran are preventable. Access to healthcare services may lead to early diagnosis of preventable causes of VI. Further well-designed studies and national surveys should be conducted to provide accurate data from different regions of Iran.

Rapid Assessment of Avoidable Blindness in Kurdistan, Iran

Purpose:

To determine the magnitude and causes of blindness and visual impairment (VI) in Kurdistan, using the Rapid Assessment of Avoidable Blindness methodology.

Methods:

In this population-based cross sectional study, 99 clusters were selected through probability proportional to size sampling. Visual acuity (VA) was measured using a standard tumbling “E” chart. Ophthalmologists examined participants with VA < 6/18 in both eyes. The cause of VI in the better eye or the most treatable cause was considered as the primary cause of VI.

Results:

A total of 3203 (response rate: 92.4%) individuals aged 50 years and older participated, of whom 1657 (51.7%) were female. The standardized prevalence of blindness, severe visual impairment (SVI), and moderate visual impairment (MVI) based on available correction (presenting VA) were 2.1% (1.5-2.6), 1.7% (1.2-2.2), and 9.6%(8.4-10.8), respectively. The proportion of avoidable causes of blindness, SVI, and MVI were 58.1%, 78.4%, and 83.4%, respectively. The most common cause of blindness and SVI was cataract (27.4% and 60.8% respectively), followed by age-related macular degeneration (25.8% and 13.7%, respectively). The leading causes of MVI were uncorrected refractive errors (RE) (37.2%) and cataract (33.6%).

Conclusion:

The prevalence of blindness in the study population seems comparable to the region. According to our results, blindness, SVI, and MVI were mostly due to avoidable causes. Cataract and refractive errors are the principal causes of blindness and VI in Kurdistan.

Prevalence and Major Causes of Visual Impairment in Iranian Adults: A Systematic Review

PURPOSE:

The purpose of this study is to provide a pooled estimate of moderate-to-severe visual impairment (MSVI) and blindness in Iran for people 50 years and over and to identify the major causes through systematic review.

MATERIALS AND METHODS:

International (PubMed, ISI Web of Science, and Scopus) and national databases (Scientific Information Database, Barakat Knowledge Network System, Iran Databank of Ophthalmology Research, and Magiran) databases were searched. Following relevance assessment and critical appraisal, eight studies were included. A funnel plot was drawn to explore the stability for estimation. Single-variable meta-regression analysis was applied for heterogeneity assessment, and a random effect model was used (but no significant source for the observed heterogeneity was found).

RESULTS:

Age-standardized pooled estimate of MSVI was 4.24% (95% confidence interval [CI]: 2.92–5.56); 3.98% (95% CI: 2.37–5.59) for men, and 4.08% (95% CI: 2.95–5.21) for women. Blindness (visual acuity <3/60) prevalence was 1.31% (95% CI: 1.23–1.39); 0.96% (95% CI: 0.89–1.03) for men, and 1.13% (95% CI: 1.06–1.20) for women. Causes of visual impairment (VI) were cataract (40.23%), amblyopia (12.03%), corneal opacity (9.63%), age-related macular degeneration (9.31%), diabetic retinopathy (4.94%), and glaucoma (3.67%).

CONCLUSION:

VI prevalence in the 50 years and older population in Iran seems significantly better than the corresponding global estimates. A rough 60% rate of treatable VI was estimated, mostly attributable to unoperated cataract.

The prevalence of visual impairment and blindness in underserved rural areas: a crucial issue for future

PurposeTo determine the prevalence of visual impairment and blindness in underserved Iranian villages and to identify the most common cause of visual impairment and blindness.Patients and methodsMultistage cluster sampling was used to select the participants who were then invited to undergo complete examinations. Optometric examinations including visual acuity, and refraction were performed for all individuals. Ophthalmic examinations included slit-lamp biomicroscopy and ophthalmoscopy. Visual impairment was determined according to the definitions of the WHO and presenting vision.ResultsOf 3851 selected individuals, 3314 (86.5%) participated in the study. After using the exclusion criteria, the present report was prepared based on the data of 3095 participants. The mean age of the participants was 37.6±20.7 years (3-93 years). The prevalence of visual impairment and blindness was 6.43% (95% confidence interval (CI): 3.71-9.14) and 1.18% (95% CI: 0.56-1.79), respectively. The prevalence of visual impairment varied from 0.75% in participants aged less than 5 years to 38.36% in individuals above the age of 70 years. Uncorrected refractive errors and cataract were the first and second leading causes of visual impairment; moreover, cataract and refractive errors were responsible for 35.90 and 20.51% of the cases of blindness, respectively.ConclusionThe prevalence of visual impairment was markedly high in this study. Lack of access to health services was the main reason for the high prevalence of visual impairment in this study. Cataract and refractive errors are responsible for 80% of visual impairments which can be due to poverty in underserved villages.