Changes to central visual fields in cases of severe myopia in a Chinese population.

BACKGROUND: Severe myopia (SM) is commonly defined as a refractive error that exceeds -10.0 diopters (D). To date, however, studies focusing on visual field changes in eyes affected by SM remain scarce. The present study aims to characterize changes to central visual fields in the presence of SM among Chinese individuals and to provide evidence for enabling early diagnosis of primary open-angle glaucoma (POAG) in cases of SM. METHODS: The data of 26 cases (44 eyes) involving Chinese individuals with SM were collected using a Humphrey Visual Field Analyzer 750i. The following aspects were identified: types of visual field defects in the probability map of pattern standard deviation, the features of patterns in visual field defects in four quadrants, the frequencies of scotomas, and the proportions of relative scotomas. RESULTS: (I) Among all visual field defects, 95.45% were found to be relevant to selected ocular fundus changes; (II) the proportion of relative scotomas was 65.02%. The two major types of visual field scotomas were the enlargement of the physiologic blind spot (43.20%) and central scotoma (38.64%), while additional types included nasal step defects (18.18%), paracentral scotomas (13.64%), and temporal sector-shaped defects (9.09%). The proportions for scotomas in the four quadrants were: 38.74% (superior temporal quadrant), 25.87% (inferior temporal quadrant), 19.32% (superior nasal quadrant), and 16.07% (inferior nasal quadrant). CONCLUSIONS: (I) Visual field analysis should be conducted alongside consideration of fundus changes. The bulk of visual field defects were found to be relative scotomas. (II) Scotomas in SM patients were mainly due to the enlargement of a physiological blind spot and central scotomas, and nasal arch-shaped scotomas presented as arc-shaped damage. (III) Abnormal scotomas were detected most frequently in the inferior temporal quadrant.

Cataract Surgical Coverage and Visual Acuity Outcomes in Rural China in 2014 and Comparisons With the 2006 China Nine-Province Survey.

PURPOSE: To estimate surgical coverage of cataract-related vision impairment and blindness and visual acuity outcomes in operated eyes in rural China in 2014 with comparisons with the 2006 Nine-Province Survey. DESIGN: Population-based, cross-sectional study. METHODS: Geographical cluster sampling was used in randomly selecting residents from a rural county or semi-rural district within 9 provinces: Beijing, Jiangsu, Guangdong, Heilongjiang, Jiangxi, Hebei, Ningxia, Chongqing, and Yunnan. Persons 50 years of age or older were enumerated through household visits and invited to examination sites for visual acuity testing and ocular examination. Surgical coverage and visual acuity outcomes in 2014 were compared with data from the 2006 survey. RESULTS: Among 51 310 examined persons, surgical coverage among those presenting with cataract-related severe visual impairment or blindness (<20/200) was 62.7% overall, ranging from 43.4% to 83.6% across the 9 study sites. Unoperated cataract was significantly associated with older age, female sex, and lack of education. Presenting visual acuity outcomes ≥ 20/63 in cataract-operated eyes was 62.2% overall, ranging from 51.6% to 78.6%, and 75.2%, ranging from 67.1% to 81.5%, with best-corrected visual acuity. As a proportional percentage of cataract surgical coverage in 2006, overall surgical coverage increased by 81.4% during the 2006-2014 interval, and by 110% when adjusted for visual acuity outcomes ≥ 20/63. CONCLUSIONS: Cataract blindness control is well underway in rural China, as evidenced by significant increases in cataract surgical coverage and improvement in visual acuity outcomes during the 2006-2014 interval. Further efforts are needed to provide greater access to affordable cataract surgery for the elderly, female persons, and those with little or no education.

Prevalence of Vision Impairment in Older Adults in Rural China in 2014 and Comparisons With the 2006 China Nine-Province Survey.

PURPOSE: To estimate the prevalence of vision impairment and blindness in 2014 among older adults in rural China with comparisons with the 2006 Nine-Province Survey. DESIGN: Population-based, cross-sectional study. METHODS: Geographical cluster sampling was used in randomly selecting residents from a rural county or semi-rural district within 9 provinces: Beijing, Jiangsu, Guangdong, Heilongjiang, Jiangxi, Hebei, Ningxia, Chongqing, and Yunnan. Persons 50 years of age or older were enumerated through household visits and invited to examination sites for visual acuity testing and examination. Vision impairment and blindness in 2014 was compared with data from the 2006 survey. RESULTS: Among 51 310 examined persons, the prevalence of presenting vision impairment (<20/63 to ≥20/400) in the better-seeing eye ranged from 6.05% to 15.3% across the 9 study sites, with presenting blindness (<20/400) ranging from 0.66% to 5.35%. With best-corrected visual acuity, the prevalence of vision impairment ranged from 1.96% to 8.74%, and blindness from 0.47% to 5.01%. Vision impairment was associated with older age, female sex, and little or no education. The overall prevalence of presenting vision impairment and blindness decreased during the 2006-2014 interval by 6.31% and 29.0%, respectively; and by 16.1% and 38.0%, respectively, after standardization of 2006 prevalence rates to the 2014 population. CONCLUSIONS: Substantial progress has been made in the reduction of vision impairment in rural China. Nevertheless, vision impairment remains an important public health problem with substantial geographic disparities and with older age, female sex, and illiteracy as risk factors.

Epidemiology of Reduced Visual Acuity among Chinese Multiethnic Students.

SIGNIFICANCE: Data regarding the epidemiology of reduced visual acuity (VA) among multiethnic children and adolescents in China are few. Understanding the vision-related health inequalities among different ethnic groups is crucial for health resource allocations and clinical managements for eye diseases. PURPOSE: We aim to determine the prevalence, main causes, and health inequalities of reduced VA in multiethnic school students in rural China. METHODS: A school-based eye survey including 7681 multiethnic school students aged 5 to 16 years in the southwestern part of China was conducted. Detailed ocular examinations including VA measurements, ocular motility evaluations, bilateral postcycloplegic refractions, and the assessments of the external eye, anterior segment, media, and retinal fundus were carried out by trained research vision professionals. Visual acuity was measured using a logarithm of the minimum angle of resolution E-chart, and reduced VA was defined as a presenting VA of worse than 20/40. Concentration index was initiatively utilized to measure health inequalities among different ethnic groups. RESULTS: The prevalence of reduced VA was 11.4 per 100 children (95% confidence interval, 10.7 to 12.1%) based on the worse-seeing eye data. The prevalence of reduced VA increased with increasing age (P < .001 for trend) and was higher among girls compared with boys (P < .0001). Uncorrected refractive error was the principal cause for reduced VA, which accounted for 87.3% of the participants with reduced VA. The concentration index for reduced VA was 0.07 among different ethnic groups. CONCLUSIONS: Compared with the estimates reported from previous studies on Chinese children and adolescents, a relatively lower prevalence of reduced VA was observed among multiethnic school students in rural China. Ethnic variations and health inequalities of reduced VA were not significant in this study.

Longitudinal Cohort Study on the Incidence of Primary Open-Angle Glaucoma in Bai Chinese.

PURPOSE: The prevalence of primary open-angle glaucoma (POAG) in China has been reported previously, and was lower than that in white and black populations. However, the incidence of POAG in China has not been reported. Therefore, a longitudinal study was conducted to determine the 5-year cumulative incidence and predictors of POAG in China. DESIGN: Population-based cohort study. METHODS: A total of 1520 participants (71.3% of the subjects in the baseline survey) of Bai ethnicity were examined and followed for 5 years. Glaucoma was defined based on the International Society of Geographical and Epidemiological Ophthalmology Classification criteria. Multivariable logistic regression models were fitted to calculate odds ratios (ORs) and 95% confidence intervals (95% CIs). RESULTS: A total of 19 new cases of POAG were detected. The 5-year cumulative incidence of POAG was 1.3% (95% CI, 0.7-1.9). In multivariate analyses, incident POAG was associated with baseline variables including increased age (OR, 4.3; 95% CI, 1.4-13.8; P = .02; 70 years or older vs 50-59 years), elevated IOP (OR, 3.5; 95% CI, 2.0-5.9; P < .001; per 10 mm Hg increase), lower education level (OR, 0.3; 95% CI, 0.1-0.8; P = .02; post-primary education vs no formal education), and the presence of myopia (OR, 3.4; 95% CI, 1.3-8.6; P < .01). CONCLUSIONS: The average annual incidence of POAG in Bai Chinese was lower than that in populations of African descent and white race. The results are important to elucidate the racial/ethnic difference in POAG incidence and for the clinical management and health resource allocation in China.

Prevalence, types and awareness of glaucoma in a multi-ethnic population in rural China: the Yunnan Minority Eye Study.

PURPOSE: To determine the prevalence, types and awareness of glaucoma in a rural community in China and to examine possible ethnic variations. METHODS: The Yunnan Minority Eye Study was a multi-ethnic community-based eye survey using random cluster sampling strategies. 2133 Bai, 2205 Han and 2208 Yi Chinese aged 50 years or older participated in this study. Glaucoma including primary open-angle glaucoma (POAG), primary angle-closure glaucoma (PACG) and secondary glaucoma was defined based on the International Society of Geographical and Epidemiological Ophthalmology criteria. RESULTS: The overall age-standardized prevalence of all glaucoma was 2.6% (95% confidence interval [CI]: 2.2-3.1%) in this population. It was 1.8% (95% CI: 1.1-1.9%) for POAG and 0.5% (95% CI: 0.9-1.6%) for PACG, respectively. Among 29 people with secondary glaucoma, 27 (93%) were blind in at least one eye. The presence of primary open-angle glaucoma was associated with male gender (odds ratio [OR] = 2.94; comparing men with women), Yi ethnicity (OR = 2.27; comparing Yi with Han people), higher IOP (OR = 1.09 per mmHg increase), and the presence of myopia (OR = 1.84). Of the 212 participants with glaucoma, only 38 (18%) were aware of the disease and had been diagnosed previously as having glaucoma or suspected glaucoma. Patients who were better educated tended to be aware of the disease. CONCLUSIONS: Significant ethnic difference in the prevalence of POAG was observed in this study. The low awareness of glaucoma highlights the pressing need to increase public awareness of this potentially blinding condition in rural China.

Estimated Cerebrospina Fluid Pressure and the 5-Year Incidence of Primary Open-Angle Glaucoma in a Chinese Population.

PURPOSE: We aim to assess the longitudinal association between baseline estimated cerebrospinal fluid pressure (CSFP) and 5-year incident primary open angle glaucoma (POAG) in a population-based sample of Bai Chinese living in rural China. METHODS: Among the 2133 Bai Chinese aged 50 years or older who had participated in the baseline examination of the Yunnan Minority Eye Study, 1520 (71.3%) attended the follow-up examination after five years and 1485 were at risk of developing POAG. Participants underwent comprehensive ophthalmic examinations at both baseline and follow-up surveys. CSFP in mmHg was estimated as 0.55 × body mass index (kg/m2) + 0.16 × diastolic blood pressure (mmHg)-0.18 × age (years)-1.91. Glaucoma was defined using the International Society of Geographical and Epidemiological Ophthalmology Classification criteria. Multivariate logistic regression models were established to determine the association between baseline CSFP and incident POAG. RESULTS: After a mean follow-up time of 5 years, 19 new cases of POAG were detected, with an incidence rate of 1.3% (95% confidence interval, 0.7-1.9%). In multivariate logistic regression analysis, after adjusting for age, gender, education, intraocular pressure, central corneal thickness, hypertension and diabetes, no significant associations, nor any trends, were evident between baseline estimated CSFP and incident POAG. The association between estimated CSFP per mmHg increase in baseline and 5-year incidence of POAG was also non-significant, with adjusted relative risk of 0.96 (P = 0.11) in multivariate analysis. CONCLUSIONS: This longitudinal cohort study does not support previously observed cross-sectional association between estimated CSFP and POAG in population-based studies.

Ethnic Variations in Pterygium in a Rural Population in Southwestern China: The Yunnan Minority Eye Studies.

PURPOSE: To determine the prevalence and associations of pterygium in a multiethnic adult population in rural China and to examine potential ethnic differences Methods: A total of 6418 adults (2133 ethnic Bai, 2130 ethnic Yi, and 2155 ethnic Han) aged 50 years or older participated in the study. Anterior segment examination was performed without pupil dilation using a slit lamp. Pterygium was defined as a raised fleshy triangular fibrovascular tissue growth of the conjunctiva encroaching onto a clear cornea. RESULTS: Pterygium was least prevalent among adults of Yi ethnicity (29.5%) compared with Bai (39.0%, p < 0.001) or Han (39.5%, p < 0.001) ethnicities. Those of Bai ethnicity were most likely to be affected by severe pterygium (7.5%), while Yi were least likely to be affected (3.8%). Multivariate analysis revealed that increasing age (odds ratio, OR, 1.017), female sex (OR 1.53), lower educational level (OR 1.25), higher blood pressure levels (OR 1.002), and greater time spent outdoors per day (OR 1.09) were significantly associated with a higher prevalence of pterygium, while Yi ethnicity (OR 0.65, comparing Yi with Han) and wearing brimmed hats outdoors (OR 0.82) were protective factors. CONCLUSION: Ethnicity was significantly associated with prevalence of pterygium. Our findings may be applicable to many other countries located within the "pterygium belt" for health resource allocation among different ethnic groups.

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

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.

Large variations in ocular dimensions in a multiethnic population with similar genetic background.

We aimed to describe the ethnic variations in ocular dimensions among three ethnic groups with similar genetic ancestry from mainland of China. We included 2119 ethnic Bai, 2202 ethnic Yi and 2183 ethnic Han adults aged 50 years or older in the study. Ocular dimensions including axial length (AL), anterior chamber depth (ACD), vitreous chamber depth (VCD) and lens thickness (LT) were measured using A-scan ultrasonography. Bai Chinese had longer ALs (P < 0.001), deeper ACDs (P < 0.001) but shallower VCDs (P < 0.001) compared with the other two ethnic groups. There were no ethnic variations in LTs. Diabetes was associated with shallower ACDs and this association was stronger in Bai Chinese compared with Yi or Han Chinese (P for interaction = 0.02). Thicker lenses were associated with younger age (P = 0.04), male gender (P < 0.001), smoking history (P = 0.01), alcohol intake (P = 0.03), the presence of cataract (P < 0.001), and the presence of diabetes (P < 0.001). There were significant differences in ocular dimensions among different ethnic groups with small differences in genetics but large variations in cultures and lifestyles.

Myopia among school students in rural China (Yunnan).

PURPOSE: We described the prevalence and associated factors of myopia and high myopia in school children of different ethnicities in a rural community in Yunnan province, China. METHODS: A total of 7681 (93.4%) primary and secondary school students aged 5-16 years in Mangshi participated in this study. Cycloplegic refraction was performed using an auto-refractor. Information regarding demographic factors, socioeconomic status and lifestyle-related exposures were collected using a questionnaire. Multivariate logistic regression models were fitted to estimate the risk factors for myopia and high myopia. RESULTS: The overall prevalence of myopia and high myopia was 39.1% (95% confidence interval [CI]: 38.0, 40.2) and 0.6% (95% CI: 0.4, 0.8) in this study. Myopia prevalence increased significantly with increasing age (p for trend <0.001). Girls were more likely to have myopia compared with boys (p < 0.001). In multivariate analysis, the presence of myopia was associated with increasing height (odds ratio [OR] = 1.02; 95% CI: 1.01, 1.03), computer use (OR = 1.17; 95% CI: 1.03, 1.32), having myopic father (OR = 1.56; 95% CI: 1.24, 1.94), having myopic mother (OR = 1.33; 95% CI: 1.08, 1.63), and increasing time on reading (OR = 1.18; 95% CI: 1.09, 1.28) after adjusting for age, sex and ethnicity. CONCLUSIONS: Nowadays myopia but not high myopia is prevalent among school children in rural China. Significant ethnic differences in myopia prevalence were not observed. A significant 'cohort effect' of myopia previously observed in urban cities had occurred in rural communities in China.

Five-Year Incidence and Predictors for Pterygium in a Rural Community in China: The Yunnan Minority Eye Study.

PURPOSE: To determine the 5-year cumulative incidence of pterygium and its associated predictors in the Bai Chinese population in a rural community. METHODS: This population-based study included 2133 subjects aged 50 years or older in 2010 and was repeated in 2015 with 1520 subjects (71.3%) participating in the follow-up examination. Participants with pterygium in either eye in 2010 were excluded from the analysis related to incidence. Anterior segment examination was performed without pupil dilation using a slit lamp, and pterygium was defined as a raised fleshy triangular fibrovascular tissue growth of the conjunctiva encroaching onto the clear cornea. RESULTS: The 5-year cumulative incidence of pterygium was 6.8% [95% confidence interval (CI), 5.2-8.4] and was significantly higher in women compared with men (8.8% vs. 3.8%; P = 0.003). The age-specific incidence was 7.7%, 6.5%, and 5.6% in those aged 50-59, 60-69, 70 years, or older at the baseline, respectively. Outdoor occupation was the only predictor, which remained to be significantly associated with a higher incidence of pterygium in multivariate analysis (odds ratio = 2.52, 95% CI, 1.27-4.95). The predictive effect of outdoor occupation on incident pterygium was moderate with an area under the curve in the receiver operating characteristic analysis of 0.59 (95% CI, 0.53-0.66). CONCLUSIONS: The incidence of pterygium in this rural cohort was higher compared to a previous report in Chinese in urban areas. The findings are important for health policy makers to project future burden of pterygium and make proper decisions on health resource allocation.

Ethnic Variations in Central Corneal Thickness in a Rural Population in China: The Yunnan Minority Eye Studies.

PURPOSE: To describe the ethnic differences in central corneal thickness (CCT) in population-based samples of ethnic Bai, Yi and Han people living in rural China. METHODS: 6504 adults (2119 ethnic Bai, 2202 ethnic Yi and 2183 ethnic Han) aged 50 years or older participated in the study. Each subject underwent standardized ocular examinations and interviewer-administered questionnaires for risk factor assessment. CCT was measured for both eyes using an ultrasound pachymeter. Regression and principal component analysis were performed to examine the relationship of ethnicity and other factors with CCT. RESULTS: The mean CCT readings were 536.4 ± 34.2 µm in ethnic Bai, 532.1 ± 32.1 µm in ethnic Yi and 529.6 ± 32.7 µm in ethnic Han adults (P<0.001), respectively. There was a decreasing trend of mean CCT with increasing age across all ethnic groups. In multivariate linear regression models, increasing CCT was associated with younger age (P<0.001), male gender (P<0.001), Bai (P<0.001) or Yi (P<0.001) ethnicity, greater body mass index (P<0.001), higher systolic blood pressure (P<0.001), greater corneal curvature (P<0.001), deeper anterior chamber (P < 0.001), and thicker lens (P<0.001). Ethnicity contributed significantly to presence of thin cornea (60%; P< 0.001) compared with other factors. CCT had similar impact on intraocular pressure readings across all ethnic groups. CONCLUSIONS: This study of more than 6500 multiethnic participants demonstrates significant ethnic variations in CCT, with Han ethnicity having the thinnest cornea compared with ethnic minorities. These data are essential to guide future multiethnic clinical trials on CCT-related ocular conditions such as glaucoma.

Ethnic variations in myopia and ocular biometry among adults in a rural community in China: the Yunnan minority eye studies.

PURPOSE: To determine the prevalence of myopia and ocular biometry in population-based samples of ethnic Yi and Han people living in an inland rural community in China. METHODS: A random cluster sampling strategy was used to select ethnic Han and Yi adults aged 50 years or older living in Yunnan. Refractive error was determined by subjective refraction and ocular biometric parameters, including axial length (AL), anterior chamber depth (ACD), vitreous chamber depth (VCD), and lens thickness (LT), which were measured using an Echoscan. RESULTS: Adults of Yi ethnicity had lower prevalence of myopia (10.3% vs. 8.1%; P = 0.02) and high myopia (2.3% vs. 1.6%; P = 0.10) than their counterparts of Han ethnicity. The prevalence of myopia increased with age (P for trend < 0.05), whereas the mean AL did not differ significantly among age groups in both ethnic groups (both P for trend > 0.05). In multivariate analysis, time spent outdoors was associated with myopia (P = 0.003) and AL (P < 0.001) but not high myopia (P = 0.33). No interaction effect was detected between ethnicity and other risk factors on myopia (all P > 0.05). Adjustment for lens nuclear opacity score reduced the excess prevalence of myopia in Han ethnicity by 37.5%. CONCLUSIONS: There was little evidence showing that ethnic disparities existed in the prevalence and risk factors between the major and minor ethnic groups living in the same communities in rural China. The "cohort effect" on myopia observed in many other populations was not seen in this study.

c-Jun N-terminal kinase 3 expression in the retina of ocular hypertension mice: a possible target to reduce ganglion cell apoptosis.

Glaucoma, a type of optic neuropathy, is characterized by the loss of retinal ganglion cells. It remains controversial whether c-Jun N-terminal kinase (JNK) participates in the apoptosis of retinal ganglion cells in glaucoma. This study sought to explore a possible mechanism of action of JNK signaling pathway in glaucoma-induced retinal optic nerve damage. We established a mouse model of chronic ocular hypertension by reducing the aqueous humor followed by photocoagulation using the laser ignition method. Results showed significant pathological changes in the ocular tissues after the injury. Apoptosis of retinal ganglion cells increased with increased intraocular pressure, as did JNK3 mRNA expression in the retina. These data indicated that the increased expression of JNK3 mRNA was strongly associated with the increase in intraocular pressure in the retina, and correlated positively with the apoptosis of retinal ganglion cells.

Prevalence, awareness, medication, control, and risk factors associated with hypertension in Yi ethnic group aged 50 years and over in rural China: the Yunnan minority eye study.

BACKGROUND: Hypertension is an important public health issue in China, but there are few studies examining hypertension in ethnic groups in Yunnan, China. This study, Yunnan Minority Eye Study (YMES), was initially designed to determine the prevalence and impact of eye diseases, including hypertension and diabetes mellitus. As a part of YMES, the prevalence, awareness, treatment, and control of hypertension and the associated risk factors among the Yi ethnic population in rural China are reported. METHODS: A population-based survey was conducted in 2012 with adult participants over 50 from rural communities in Shilin Yi Autonomous County, Yunnan Province, located in southwest China. A random cluster sampling method was used to select a representative sample. The participants' blood pressure, height, weight, and waist circumference were measured. Hypertension was defined as mean systolic blood pressure ≥140 mmHg and/or diastolic blood pressure ≥90 mmHg, and/or current use of antihypertensive medications. RESULTS: A total of 2208 adults were assessed. The prevalence of hypertension was 38.5%, and the age- and gender-adjusted prevalence was 37.0%. The proportion of patients who were aware of their hypertension among those diagnosed with hypertension was 24.8%. Of those aware of having hypertension, 23.6% took antihypertensive drugs. Among all hypertensive patients, only 7.2% had controlled their hypertension (<140/90 mmHg). Risk factors for hypertension were older age, smoking, alcohol consumption, family history of high blood pressure, overweight, and obesity. Protective factors included being slim and higher education. CONCLUSIONS: Hypertension was highly prevalent among this population of the Yi ethnic group in China. The ratio of awareness, treatment, and control of hypertension were considerately low. Hypertension education and screening programs in rural China are recommended to improve the health status of this population.

A multi-center, cross-sectional study on the burden of infectious keratitis in China.

OBJECTIVE: To understand the prevalence and demographic characteristics of infectious keratitis and infectious corneal blindness. METHODS: A multi-center, population-based cross-sectional study was conducted from January 1 to August 31, 2010. A total of 191,242 individuals of all age groups from 10 geographically representative provinces were sampled using stratified, multi-stage, random and systematic sampling procedures. A majority, 168,673 (88.2%), of those sampled participated in the study. The examination protocol included a structured interview, visual acuity testing, an external eye examination, and an anterior segment examination using a slit lamp. The causes and sequelae of corneal disease were identified using uniform customized protocols. Blindness in one eye caused by infectious keratitis was defined as infectious corneal blindness. RESULTS: The prevalence of past and active infectious keratitis was 0.192% (95% confidence interval [CI], 0.171-0.213%), and the prevalence of viral, bacterial, and fungal keratitis was 0.11%, 0.075%, and 0.007%, respectively. There were 138 cases of infectious corneal blindness in at least one eye in the study population (prevalence of 0.082% [95%CI, 0.068%-0.095%]). Statistical analysis suggested that ocular trauma, alcoholic consumption, low socioeconomic levels, advanced age, and poor education were risk factors for infectious corneal blindness. CONCLUSIONS: Infectious keratitis is the leading cause of corneal blindness in China. Eye care strategies should focus on the prevention and rehabilitation of infectious corneal blindness.

[Prevalence and causes of blindness and moderate and severe visual impairment among adults aged 50 years or above in Luxi County of Yunnan Province: the China Nine-Province survey].

OBJECTIVE: To investigate the prevalence and causes of blindness and moderate and severe visual impairment among adults aged ≥ 50 years in Luxi County of Yunnan Province, China. METHODS: It was a population-based cross-section study. Geographically defined cluster sampling was used in randomly selecting 5575 individuals aged ≥ 50 years in Luxi County. The survey was preceded by a pilot study where operational methods were refined and quality assurance evaluation was carried out. All participants were enumerated through village registers followed door-to-door visits.Eligible individuals were invited to receive visual acuity measurement and eye examination. Prevalence of blindness and moderate and severe visual impairment was calculated according to different age, gender or education. And the reasons of blindness were analyzed.Statistical analyses were performed using Stata/SE Statistical Software, release 9.0. Chi-square test was used to investigate the association of age, gender and education with presenting and best corrected visual acuity. RESULTS: Five thousands five hundreds and seventy-five individuals were enumerated and 5151 persons were examined, the response rate was 92.39%. Based on the criteria of World Health Organization visual impairment classification in 1973, the prevalence of blindness and moderate and severe visual impairment defined as best corrected visual acuity was 4.95% (255/5151) and 9.51% (490/5151) , respectively. The prevalence of blindness and moderate and severe visual impairment defined as presenting visual acuity was 5.40% (278/5151) and 15.84% (816/5151) , respectively. The prevalence of blindness and moderate and severe visual impairment was higher in aged (χ(2) = 1349.21, P = 0.000) , illiterate (χ(2) = 203.55, P = 0.000) persons. Cataract was still the first leading cause of blindness and visual impairment. CONCLUSIONS: The prevalence of blindness and moderate and severe visual impairment is highest in China Nine-Province Survey among older adults aged ≥ 50 years in Luxi County. The first leading cause of blindness and visual impairment is still cataract.

Prevalence, awareness, medication, control, and risk factors associated with hypertension in Bai ethnic group in rural China: the Yunnan Minority Eye Study.

PURPOSE: This study aimed to assess the prevalence, awareness, treatment, and control of hypertension and their associated factors among Bai ethnic population in the rural China. METHODS: A population-based survey was conducted in 2010 with a randomly cluster sampling in rural communities in Dali, southwest China. A total of 2133 adults aged 50 or above were interviewed, and their blood pressure, height, weight and waist circumference were measured. Hypertension was defined as a mean SBP≥140 mmHg and/or DBP≥90 mmHg, and/or current use of antihypertensive medications. RESULTS: The prevalence of hypertension was 42.1% (899/2133), and the age- and gender-adjusted prevalence was 40.0%. Among the hypertensive participants, 28.4% (255/899)were aware of their condition, while 24.6% (221/899) took antihypertensive medications, with only 7.5% (67/899) of those achieving blood pressure control (<140/90 mmHg). Risk factors for hypertension were older age, smoking, alcohol drinking, family history of HBP, overweight, and obesity, while protective factors included being lean, and having finished senior high school or above. CONCLUSIONS: Hypertension prevalence is high among the population of Bai ethnic group in China, while the associated risk factors of hypertension include overweight/obesity, cigarette smoking, history of hypertension, and older age. The percentages of hypertensive participants aware of their hypertension and those taking antihypertensive medications were low with an incredibly low proportion of hypertensive patients who kept their hypertension under control. It is suggested that health education and hypertension screening programs be carried out in the area for the high blood pressure prevention and control.

Prevalence and outcomes of cataract surgery in adult rural Chinese populations of the Bai nationality in Dali: the Yunnan minority eye study.

PURPOSE: To investigate the prevalence and visual acuity (VA) outcomes of cataract surgery in adults of the Bai Nationality populations in rural China. METHODS: We conducted a population-based cross-sectional survey (from randomly selected block groups) of Chinese Bai Nationality aged ≥50 years in southwestern China. Presenting visual acuity (PVA), best corrected visual acuity (BCVA) were recorded and a detailed eye examination was carried out. For all aphakic and pseudophakic subjects identified, information on the date, setting, type, and complications of cataract surgery were recorded. In eyes with VA <20/63, the principal cause of visual impairment was identified. RESULTS: Of 2133 (77.8% of 2742) subjects, 99 people (129 eyes) had undergone cataract surgery. The prevalence of cataract surgery was 4.6%. Surgical coverage among those with PVA <20/200 in both eyes because of cataract was 52.8%. Unoperated cataract was associated with older age. The main barrier to cataract surgery was lack of awareness and knowledge, cost, and fear. Among the 129 cataract-operated eyes, 22.5% had PVA of ≥20/32, 25.6% had PVA of 20/40 to 20/63, 23.3% had PVA <20/63 to 20/200, and 28.7% had PVA<20/200. With BCVA, the percentages were 42.6%, 23.3%, 10.9%, and 23.3%, respectively. Aphakia (odds ratio [OR], 8.49; P<0.001) and no education (OR, 10.18; P = 0.001) or less education (OR, 6.49; P = 0.014) were significantly associated with postoperative visual impairment defined by PVA, while aphakia (OR, 8.49; P<0.001) and female gender (OR, 4.19; P = 0.004) were significantly associated with postoperative visual impairment by BCVA. The main causes of postoperative visual impairment were refractive error, retinal disorders and glaucoma. CONCLUSIONS: Half of those with bilateral visual impairment or blindness because of cataract remain in need of cataract surgery in Bai population. Surgical uptake and visual outcomes should be further improved in the future.