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

Sponsor

Chinese University of Hong Kong (Other)

Overall Status

Completed

CT.gov ID

NCT04143334

Collaborator

(none)

3,700

Enrollment

Actual Duration (Months)

Study Details

Study Description

Brief Summary

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.

Condition or Disease	Intervention/Treatment	Phase
Blindness Cataract Visual Impairment Refractive Errors	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 Design

Study Type:

Observational

Actual Enrollment :

3700 participants

Observational Model:

Other

Time Perspective:

Cross-Sectional

Official Title:

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

Actual Study Start Date :

Apr 1, 2012

Actual Primary Completion Date :

Dec 1, 2015

Actual Study Completion Date :

Dec 1, 2016

Arms and Interventions

Arm	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

Arm

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

Outcome Measures

Primary Outcome Measures

the prevalence of blindness and visual impairment (VI) and main avoidable causes in Chaonan, China [one year]
the prevalence of blindness and visual impairment (VI), and report the avoidable causes, including cataract in Chaonan Region, Guangdong Province, southern China

Secondary Outcome Measures

the diagnostic accuracy of RAAB [one year]
To evaluate the diagnostic accuracy of Rapid Assessment of Avoidable Blindness (RAAB)

Eligibility Criteria

Criteria

Ages Eligible for Study:

50 Years and Older

Sexes Eligible for Study:

All

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.