Prevalence of Blindness, Visual Impairment in Chao Nan Area, China

Prevalence of Blindness, Visual Impairment and Main Avoidable Causes in Chao Nan Area

This study will provide a profile of blindness/visual impairment, avoidable blindness and cataract surgery service in Chaonan, mainland China. We also evaluate the diagnostic accuracy of Rapid Assessment of Avoidable Blindness (RAAB) comparison with conventional survey.

Study Overview

• Status: Completed
• Conditions: Refractive Errors; Cataract; Blindness; Visual Impairment
• Intervention / Treatment: Diagnostic test: Conventional survey

Detailed Description

This proposal describes a population-based study aimed at determining the prevalence of visual impairment, blindness and major causes in adults age 50 years old and above in Chaonan County of Guangdong province, where one of the Project Vision Charity Eye center was founded in 2009.

In the proposed study, we will examine 3700 Chaonan County residents aged 50 years and older, selected via a clustered, randomized sampling with probability proportional to size (PPS). The cluster will be at the village level, 50 subjects aged 50 years and older will be examined in each cluster includes Visual acuity, torch light, and fundus review, the major cause of blindness or visual impairment will be determined. We also randomly recruited 60% clusters,total 2250 participants, from RAAB survey to conduct a detailed conventional eye examination.

This study will provide a profile of blindness/visual impairment, avoidable blindness and cataract surgery service in Chaonan. we will evaluate the diagnostic accuracy of Rapid Assessment of Avoidable Blindness (RAAB) comparison with conventional survey. . It will provide important public health issues for the purposes of establishing a sustainable and suitable model to eliminate the cataract blindness in China.

• Study Type: Observational
• Enrollment (Actual): 3700

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 50 years and older (ADULT, OLDER_ADULT)
• Accepts Healthy Volunteers: N/A
• Genders Eligible for Study: All

• Sampling Method: Probability Sample

Study Population

Among the 3700 people, 169 (4.6%) could not be reached, 20 (0.5%) were unable to communicate, and 27 (0.7%) refused. Consequently, 3484 persons (response rate 94.2%) with a mean (±SD) age of 64.4±9.8 years were examined. These included 1397 men (40.1%) with an average age of 65.3 ±9.6 years and 2087 women (59.9%) with an average age of 63.8±9.8 years.

Of the 2145 subjects (95.3%，2145/2250), 327 (15.2%) refused, and 2 (0.1%) were unable to cooperate for examination. Consequently, 1816 subjects (1816/2145, 84.7%) with a mean (±SD) age of 64.4±9.6 years received the conventional ophthalmic examination in the mobile eye clinic (figure 1). These included 686 men (37.8%) with an average age of 65.5±9.4 years and 1130 women (62.2%) with an average age of 63.8±9.6 years.

Description

Inclusion Criteria:

• aged 50 years and above
• In each household all persons , residing in the household for six months or more over the past year
• "Residing in the household" is defined as "sharing meals from the same kitchen with the other members of the household for at least 6 months in a year. Exclude any visitors.

Exclusion Criteria:

• age <50 years old
• Visitors in the villages
• Residing in the household< 6 months

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
RAAB survey; We will examine 3700 Chaonan County residents aged 50 years and older, selected via a clustered, randomized sampling with probability proportional to size (PPS). The cluster will be at the village level, 50 subjects aged 50 years and older will be examined in each cluster includes Visual acuity, torch light, and fundus review, the major cause of blindness or visual impairment will be determined.	Diagnostic test: Conventional survey
conventional survey; All the recruited participants underwent ophthalmic examination according to the RAAB protocol and then 60% of them were re-examined with instruments in a mobile eye clinic set up in a village center on the same day. Examination in the mobile clinic included standardized visual acuity (VA) tests using logarithm of the minimum angle resolution charts, refraction, slit-lamp biomicroscopy, and dilated fundal examination with a binocular indirect ophthalmoscope.	Diagnostic test: Conventional survey

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
the prevalence of blindness and visual impairment (VI) and main avoidable causes in Chaonan, China	the prevalence of blindness and visual impairment (VI), and report the avoidable causes, including cataract in Chaonan Region, Guangdong Province, southern China	one year

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
the diagnostic accuracy of RAAB	To evaluate the diagnostic accuracy of Rapid Assessment of Avoidable Blindness (RAAB)	one year

Collaborators and Investigators

• Sponsor: Chinese University of Hong Kong
• Investigators: Principal Investigator: XIUJUAN ZHANG, PhD, Chinese University of Hong Kong

Publications and helpful links

General Publications

• Li EY, Liu Y, Zhan X, Liang YB, Zhang X, Zheng C, Jhanji V, Xu P, Chang DF, Lam DS. Prevalence of blindness and outcomes of cataract surgery in Hainan Province in South China. Ophthalmology. 2013 Nov;120(11):2176-83. doi: 10.1016/j.ophtha.2013.04.003. Epub 2013 May 25.

Study record dates

Study Major Dates

• Study Start (ACTUAL): April 1, 2012
• Primary Completion (ACTUAL): December 1, 2015
• Study Completion (ACTUAL): December 1, 2016

Study Registration Dates

• First Submitted: October 24, 2019
• First Submitted That Met QC Criteria: October 26, 2019
• First Posted (ACTUAL): October 29, 2019

Study Record Updates

• Last Update Posted (ACTUAL): October 31, 2019
• Last Update Submitted That Met QC Criteria: October 29, 2019
• Last Verified: October 1, 2019

More Information

Terms related to this study

• Keywords: diagnostic accuracy; blindness; cataract blindness
• Additional Relevant MeSH Terms: Nervous System Diseases; Eye Diseases; Neurologic Manifestations; Lens Diseases; Sensation Disorders; Refractive Errors; Cataract; Blindness; Vision, Low; Vision Disorders
• Other Study ID Numbers: CRE-2011.389

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No