A Population-based Survey of the Prevalence and Types of Glaucoma in Central Iran: The Yazd Eye Study

doi:10.1016/j.ophtha.2013.02.029

Ophthalmology

Volume 120, Issue 10, October 2013, Pages 1977-1984

https://doi.org/10.1016/j.ophtha.2013.02.029 Get rights and content

Purpose

To describe the prevalence and types of glaucoma in Yazd, central Iran.

Design

Population-based, cross-sectional study.

Participants

Iranian adults aged 40 to 80 years, residing in Yazd, Iran, in 2010 and 2011.

Methods

Eligible samples were selected using cluster random sampling. Each participant underwent an interview and ophthalmologic examinations, including refraction, determination of uncorrected and best-corrected visual acuity, slit-lamp biomicroscopy, Goldmann applanation tonometry, gonioscopy, dilated fundus examination, central corneal thickness measurement, visual field testing, and stereoscopic fundus photography.

Main Outcome Measures

Prevalence of different types of glaucoma.

Results

Of 2320 eligible individuals, 2098 (response rate, 90.4%) participated in the study and 1990 completed all evaluations for glaucoma diagnosis. Overall, 47 persons (2.4%) were categorized with ocular hypertension, 32 persons (1.6%) were categorized with primary angle-closure suspect (PACS), and 16 persons (0.8%) were categorized with primary angle closure (PAC). The total number of subjects with glaucoma was 87 (4.4%; 95% confidence interval, 3.3–5.4), consisting of primary open-angle glaucoma (POAG, 3.2%, including high-tension glaucoma [1.7%] and normal-tension glaucoma [NTG], 1.5%]), primary angle-closure glaucoma (PACG, 0.4%), pseudoexfoliation glaucoma (0.4%), and other secondary glaucomas (0.4%). The mean age of subjects with glaucoma was 63.3±11 years, and 57.5% of them were female. Seventy-eight individuals (89.7%) were unaware of their disease. Positive family history of glaucoma was present in 6.9% of glaucoma subjects.

Conclusions

The prevalence of glaucoma in Yazd (4.4%) is comparable to that in other population-based studies in Asia, with POAG accounting for the majority of cases. Most affected subjects were unaware of their disease.

Financial Disclosure(s)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Section snippets

Methods

This population-based, cross-sectional study targeted residents of Yazd Province who were aged 40 to 80 years. This province is located in central Iran and has an estimated 526 000 residents in 2010–2011 according to the 2006 National Census. The study adhered to the Declaration of Helsinki and was approved by the ethics committee at Shahid Beheshti University of Medical Sciences. By using multiple-stage systematic and cluster randomization and with probability proportional to size strategy, 58

Results

In this study, 2098 of 2320 eligible persons participated in ophthalmologic evaluations (response rate of 90.4%), but eventually 1990 subjects with a mean age of 54.1±10.1 years, including 922 men (46.3%) and 1068 women (53.7%), completed all examination necessary to ascertain a diagnosis of glaucoma (rate of complete analyzed data = 85.7%; Table 1). Participants from urban areas comprised the majority of samples (1871 [89.2%] vs. 227 [10.8%] rural residents).

In this population, 47 subjects

Discussion

This study provides information on the prevalence and types of glaucoma in one of the central regions of Iran based on ISGEO criteria. Multiple studies have been conducted worldwide to determine the prevalence of glaucoma and have used different criteria to define glaucoma. Appropriate definitions are the mainstay of epidemiologic studies. The ISGEO classification uses both structural and functional parameters for glaucoma diagnosis.⁹ Table 7 compares data from studies that have been conducted

Acknowledgments

The authors thank Drs. Reza Zaraee and Yadollah Eslami for help in providing equipment and to Drs. Mahmood Ghassami, Navid Nilforooshan, and Sassan Moghimi for extensive statistical assistance and support in completing this work.

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In addition, a considerable number of children in the Saudi population have vernal keratoconjunctivitis, with continuous ocular inflammation and eye rubbing, resulting in a compromised ocular surface that is more vulnerable to friction against the eyelids, melting, and subsequent implant exposure.39 Although the results of the current study did not find a similar association, inferior GDD implantation has been reported as a risk factor for implant exposure in both adult40 and pediatric41 glaucoma patients. This was attributed to the anatomical difference between the superior and inferior fornices, where the latter is characterized by a shorter recess and lesser conjunctival tissue for implant coverage, as well as less eyelid coverage, increasing the chances of implant exposure.40
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We conducted a systematic review and meta-analysis of population-based studies published between January 1, 1990, and June 1, 2020. Article search was conducted in online databases (PubMED, Web-of-Science), grey literatures (OpenGrey), and nongovernment organization reports. Our outcome measure was the proportion of glaucoma cases that were undetected previously. Manifest glaucoma included any form of glaucoma reported in the original studies and may include primary open-angle glaucoma (POAG), primary angle-closure-glaucoma, secondary glaucoma, or a combination thereof. Undetected glaucoma was defined as glaucoma cases that were undetected prior to diagnosis in the respective study. Random-effect meta-analysis was used to estimate the pooled proportion of undetected glaucoma. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and the Meta-analysis of Observational Studies in Epidemiology guidelines in our study.
We identified 61 articles from 55 population-based studies (n = 189 359 participants; n = 6949 manifest glaucoma). Globally, more than half of all glaucoma cases were undetected previously on average in each geographical region. Africa (odds ratio [OR], 12.70; 95% confidence interval [CI], 4.91–32.86) and Asia (OR, 3.41; 95% CI, 1.63–7.16) showed higher odds of undetected glaucoma as compared with Europe. Countries with low Human Development Index (HDI; <0.55) showed a higher proportion of undetected manifest glaucoma as compared with countries of medium to very high HDI (≥0.55; all P < 0.001). In 2020, 43.78 million POAG cases were projected to be undetected, of which 76.7% were in Africa and Asia.
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: Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

: This study is financially supported by the Ophthalmic Research Center at Shahid Beheshti University of Medical Sciences, and Tehran and Yazd Medical Universities.

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Original articleA Population-based Survey of the Prevalence and Types of Glaucoma in Central Iran: The Yazd Eye Study

Purpose

Design

Participants

Methods

Main Outcome Measures

Results

Conclusions

Financial Disclosure(s)

Section snippets

Methods

Results

Discussion

Acknowledgments

Ophthalmology

Ophthalmology

Ophthalmology

Ophthalmology

Ophthalmology

Ophthalmology

Ophthalmology

Ophthalmology

Global data on visual impairment in the year 2002

Bull World Health Organ

Number of people with glaucoma worldwide

Br J Ophthalmol

The number of people with glaucoma worldwide in 2010 and 2020

Br J Ophthalmol

Glaucoma in Mongolia: a population-based survey in Hovsgol province, northern Mongolia

Arch Ophthalmol

Prevalence of glaucoma in rural Myanmar: the Meiktila Eye Study

Br J Ophthalmol

Intraocular pressure, central corneal thickness, and glaucoma in Chinese adults: the Liwan Eye Study

Am J Ophthalmol

Prevalence of glaucoma in North China: the Beijing Eye Study

Am J Ophthalmol

Original article
A Population-based Survey of the Prevalence and Types of Glaucoma in Central Iran: The Yazd Eye Study