Elsevier

Ophthalmology

Volume 122, Issue 7, July 2015, Pages 1480-1488
Ophthalmology

Original article
Prevalence and Causes of Visual Impairment in a Chinese Adult Population: The Taizhou Eye Study

https://doi.org/10.1016/j.ophtha.2015.03.022Get rights and content

Purpose

To study the current prevalence and causes of low vision and blindness in an adult Chinese population.

Design

Population-based, cross-sectional study.

Participants

We used a random cluster sampling method and evaluated 10 234 eligible subjects ≥45 years old (response rate, 78.1%) in the Taizhou Eye Study.

Methods

Examinations were performed from July 2012 through December 2013. Participants underwent a detailed examination, including uncorrected visual acuity, best-corrected visual acuity (BCVA), intraocular pressure, axial length, slit-lamp, and fundus examinations to evaluate the prevalence and primary causes of visual impairment (VI).

Main Outcome Measures

We defined low vision and blindness according to the World Health Organization (WHO) criteria (low vision: BCVA, <20/63–≥20/400; blindness: BCVA, <20/400 in the better eye) and United States criteria (low vision: BCVA, <20/40–≥20/200; blindness: BCVA, <20/200 in the better eye).

Results

Using the WHO BCVA criteria, the standardized prevalence of bilateral low vision and blindness were 5.1% and 1.0%, respectively. Using the United States BCVA criteria, the standardized prevalence were 12.8% and 1.5%, respectively. Using the WHO criteria, the primary causes of bilateral low vision and blindness were cataract (59.1% and 48.5%, respectively), myopic macular degeneration (17.6% and 17.2%, respectively), and age-related macular degeneration (11.6% and 10.1%, respectively). The primary causes of monocular low vision were cataract (55.6%), age-related macular degeneration (12.6%), and myopic macular degeneration (8.9%), whereas those of monocular blindness were cataract (46.8%), atrophy of eyeball or prosthetic eye (10.2%), and cornea opacity (7.3%). A further analysis revealed that in adults 45-59 years old, myopic macular degeneration (59.6% and 27.2%, respectively) and cataract (13.8% and 23.4%, respectively) were the leading causes of bilateral and monocular VI. In adults ≥60 years old, cataract (66.8% and 61.2%, respectively) and age-related macular degeneration (12.6% and 11.8%, respectively) were the primary causes of bilateral and monocular VI.

Conclusions

The prevalence of low vision and blindness in Chinese adults remains a severe public health problem. In the Taizhou Eye Study, cataract was the leading cause of low vision and blindness. Myopic macular degeneration and cataract were the primary causes of VI in adults 45-59 years and ≥60 years old, respectively.

Section snippets

Study Design and Procedure

The Taizhou Eye Study was part of the Taizhou Longitudinal Study,21 which is an ongoing large-scale, population-based cohort study initiated by Fudan University and supported by the National Science and Technology Ministry since 2007. For the Taizhou Eye Study, we performed a baseline ophthalmologic examination between July 2012 and December 2013 in Taizhou. We used a random cluster sampling method and constructed a sampling frame based on the Public Security Bureau and Community Committee. We

Results

Among the 13 106 individuals 45 years of age or older who enrolled in the study, 10 326 (response rate, 78.8%) underwent the eye examination. Of these 10 326 subjects, 92 subjects could not provide reliable visual acuity answers because of a mental or physical disorder. As a result, 10 234 eligible residents completed the eye study (total response rate, 78.1%). The mean age of the participants was 59.5±9.8 years (median, 59 years; age range, 45–100 years), which was similar to the mean age of

Discussion

This study describes in detail the current prevalence and causes of low vision and blindness among the Chinese adult population in Taizhou. We used the age- and gender-standardized ratio from the 2012 China census. This study estimated that approximately 24.3 million people have low vision and that 4.65 million people are blind in mainland China, according to the WHO standard. Cataract was the leading cause of bilateral low vision and blindness in mainland China, followed by myopic macular

Acknowledgments

The authors thank Dr. Walter J. Stark, Dr. David S. Friedman, Dr. Sheila West, and Dr. Jing Tian from Johns Hopkins Hospital, Wilmer Eye Institute, for their helpful advice and technical support. The authors also thank the members of the Taizhou Eye Study team for their contribution to this study.

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    Supplemental material is available at www.aaojournal.org.

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

    Supported by the Natural Science Foundation of China, Beijing, China (grant no.: NSFC81270989); Key Projects in the National Science & Technology Pillar Program, Beijing, China (grant no.: 2011BAI09B00); New One Hundred People's Plan of Shanghai Health Bureau, Shanghai, China (grant no.: XBR2011056); and Visual Impairment and Reconstruction Key Laboratory of Shanghai, Shanghai, China (grant no.: 12DZ2260500).

    Author Contributions:

    Conception and design: Tang, X. Wang, J. Wang, Lu

    Analysis and interpretation: Tang, X. Wang, J. Wang, Lu

    Data collection: Tang, Huang, Gao, Luo, Lu

    Obtained funding: X. Wang, J. Wang, Lu

    Overall responsibility: Tang, Lu

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