Population-based assessment of visual impairment among ethnic Dai adults in a rural community in China

Abstract

Dai ethnicity is one of the major Chinese ethnic minorities with a population of about 1.2 million. We aimed to determine the prevalence and potential causes of visual impairment (VI) among ethnic Dai adults aged 50 years or older in a rural community in China. A population-based survey including 2163 ethnic Dai people (80.5%) was undertaken using a random cluster sampling strategy. The detailed eye examination was performed after pupil dilation by trained study ophthalmologists and optometrists. Presenting visual acuity (PVA) and best-corrected visual acuity (BCVA) was measured using the Early Treatment Diabetic Retinopathy Study logMAR chart and VI was defined as a VA of less than 20/63 in the better-seeing eye. The overall prevalence of presenting blindness and low vision was 3.0% (95% CI, 2.3–3.7) and 13.3% (95% CI, 11.9–14.8), respectively. The prevalence estimates were reduced to 2.1% (95% CI, 1.5–2.8) and 6.7% (95% CI, 5.7–7.8) when BCVA was considered. Men were more likely to be affected by low vision but less likely to be blind compared with women. Cataract accounted for 62.7% of presenting low vision and 68.8% of presenting blindness, respectively. In conclusion, VI was a significant health concern in Dai Chinese in China.

The prevalence and causes of visual impairment among ethnic Tujia adults in a rural community in China

“…Our research has many similarities with the studies of the ethnic Bai and Dai that were conducted by The Yunnan Minority Eye Studies, [ 18 , 19 ] such as the sampling strategies used, the definitions of the outcomes and the age ranges of the study subjects. Therefore, the results for the 3 ethnic groups can be directly compared.…”

“…The prevalence of presenting VI was lower among the Tujia ethnic population than among the Bai and Dai ethnic groups. [ 18 , 19 ] Studies have pointed out that due to the lack of medical and health services (lack of cataract surgery), the prevalence of visual impairment in rural areas is higher. [ 20 ] Based on our study, cataract surgery is an important factor when estimating the prevalence of VI.…”

“…[ 20 ] Based on our study, cataract surgery is an important factor when estimating the prevalence of VI. The proportion of VI caused by cataracts was 15.17%, which was higher than that of the Bai (4.6%) [ 18 ] and Dai (8.9%) [ 19 ] populations possibly due to the Health Express Project which is a free cataract surgery program to solve the vision problem in rural China. [ 20 ]…”

Prevalence and causes of low vision and blindness in Baotou

“…[ 8 ] The studies estimating the prevalence of blindness and low vision in China published from January 2010 to April 2016 were searched and presented in Table 6 . [ 4 , 9 – 20 ] Although the estimating criteria for blindness and low vision differed among studies, Table 6 shows that according to the BCVA in better eye, previous studies reported that the prevalence rates of blindness and low vision were 0.2% to 2.88% and 1.4% to 10.41% in China, respectively. In rural of Kailu County, Inner Mongolia, the overall prevalence rates of blindness and low vision based on BCVA were 0.9% and 7.52%, respectively.…”

Dichotomous Keys in the Botanical Learning of Non-Visual (Blind) People

“…The final size of the sample was determined on the basis of previous research that examined DK efficiency but which examined students and enthusiasts without visual impairment, and research in the field of the science education of NV students, as well as on the basis of the number of NV who wanted to voluntarily participate in the research and general recommendations for sample size in educational researches (Cohen, Manion, & Morrison, 2008). All the participants had a visual acuity of less than 3/60 and a narrowing of the field of view of 10° for their better visual eye (Yang et al, 2016). The demographic characteristics of the sample is presented in Table 1.…”