Prevalence of visual impairment and outcomes of cataract surgery in Chaonan, South China

Temporal trends and projection of blindness and vision loss prevalence in older adults in BRICS countries

BACKGROUND

Blindness and vision loss (BVL) is a major global health issue affecting older adults, but its burden in transition countries has received limited attention. Therefore, we aimed to assess the trends in the burden of BVL among older adults between 1990 and 2019 across Brazil, Russia, India, China, and South Africa (BRICS), and predict the burden by 2040.

METHODS

Data on BVL and its related causes were obtained from the Global Burden of Disease 2019 study. We investigated the temporal trends by calculating the average annual percentage change using joinpoint regression analysis. Subsequently, we performed Bayesian age-period-cohort modeling to estimate the burden of BVL and its related causes by 2040.

RESULTS

Most BRICS countries experienced a significant decline (p < 0.05) in age-standardized prevalence rates, and the decreasing trends tend to continue. However, by 2040, the number of BVL cases is expected to increase by approximately 50% across BRICS, with an estimated approximately 192, 170, 25, 17, and 7 million cases in China, India, Russia, Brazil, and South Africa, respectively. The related ranks of BVL causes are also estimated to change in the future, particularly in India.

CONCLUSIONS

The different burdens and trends of BVL across BRICS reflected the different stages of population health transition. Effective eye disease prevention requires appropriate public health interventions. Developing effective health policies and services for older adults is urgently needed in BRICS countries.

Interocular Symmetry in Retinal Nerve Fiber Layer Thickness in Children: The Hong Kong Children Eye Study

INTRODUCTION

The aim of this work is to determine the interocular differences in peripapillary retinal nerve fiber layer (p-RNFL) thickness and its associations among school children in Hong Kong.

METHODS

We conducted a population-based study including 4034 children aged 6-8 years from the Hong Kong Children Eye Study (HKCES). All participants received comprehensive ocular examinations where p-RNFL thickness was measured using spectral-domain optical coherence tomography (SD-OCT). The degree of symmetry between both eyes was analyzed and represented by intraclass correlation coefficient (ICC) values. Multivariable linear regression analysis was used to investigate the associations between ocular and systemic factors with p-RNFL thickness difference.

RESULTS

The study included 4034 children with a mean age of 7.61 ± 0.98 years. The mean global p-RNFL thickness was 106.60 ± 9.41 μm in right eyes and 105.99 ± 9.30 μm in left eyes. The ICC for global p-RNFL difference was 0.866 (95% CI 0.858-0.873, p < 0.001). The symmetry displayed the largest values in nasal inferior quadrant with the ICC value of 0.736 (95% CI 0.721-0.749); and the smallest degree of symmetry was found to be in the superior temporal quadrant with the ICC value of 0.567 (95% CI 0.546-0.588). Axial length (AL) difference was found to have more pronounced correlation to interocular symmetry in p-RNFL thickness with the coefficient of 0.514 (p < 0.001).

CONCLUSIONS

Normal variation in interocular symmetry exists in children. Our results can contribute to the establishment of a standard reference for interocular differences in OCT parameters in children. The interocular differences in AL should be considered in the interpretation of RNFL symmetry, in terms of identifying children at risk of developing glaucoma or other ocular disorders.

To investigate the individual and household-level factors influencing the willingness to pay for cataract surgery among patients aged 50 years and older in rural China: a cross-sectional study

OBJECTIVES

To investigate the factors influencing the willingness to pay (WTP) for cataract surgery among patients aged 50 years and older in rural China at both individual and household levels.

DESIGN

A cross-sectional study.

SETTING

The study was conducted in Gansu, China.

PARTICIPANTS

Patients aged ≥50 years who were diagnosed with cataracts indicated for surgery and lived rural in Gansu from October to December 2020 were included in the study.

PRIMARY AND SECONDARY OUTCOME MEASURES

The main study outcome was the patients' WTP for cataract surgery. The association of individual characteristics, knowledge about cataracts, health status and household characteristics with patients' WTP was also evaluated based on the collected data using structured questionnaires.

RESULTS

A total of 324 (85.94%) patients in the study reported that they were willing to pay for their cataract surgery. However, only 179 (47.48%) patients were willing to pay over ¥1000 to cover the cost of cataract surgery under the New Rural Cooperative Medical System (NRCMS). Patients aged 75 years and older were significantly less likely to pay for cataract surgery (p=0.037). Better visual status (p=0.032), self-reported severe poor visual status (p=0.001), higher annual household income (p=0.052) and a higher level of children's education (p=0.076) were significantly more likely to pay for cataract surgery.

CONCLUSIONS

The WTP for cataract surgery in rural China is still insufficient. More than half of patients' WTP for surgery do not cover the cost of cataract surgery after reimbursement by the NRCMS. Both individual and household characteristics contribute to the low WTP for cataract surgery.

Real-world visual outcomes of cataract surgery based on population-based studies: a systematic review

BACKGROUND/AIMS

Quantity of cataract surgery has long been an important public health indicator to assess health accessibility, however the quality of care has been less investigated. We aimed to summarise the up-to-date evidences to assess the real-world visual outcomes after cataract surgery in different settings.

METHODS

A systematic review was undertaken in October 2021. Population-based cross-sectional and longitudinal studies reporting vision-related outcomes after cataract surgery published from 2006 onward were included. A meta-analysis was not planned.

RESULTS

Twenty-six cross-sectional studies from low-income and middle-income countries (LMICs) and five cross-sectional studies from high-income countries (HICs) were included. The proportions of participants with postoperative presenting visual acuity (VA) ≥0.32 (20/60) were all over 70% in all HICS studies, but mostly below 70% in LMICS studies, ranging from 29.9% to 80.5%. Significant difference in postoperative VA was also observed within countries. The leading causes for postoperative visual impairment (defined mostly as presenting VA <20/60) mainly included refractive error, ocular comorbidities and surgical complications including posterior capsule opacification, except for one study in Nigeria wherein the leading cause was aphakia. Only four population-based cohort studies were included with 5-20 years of follow-up time, generally demonstrating no significant changes in postoperative visual outcomes during the follow-up.

CONCLUSIONS

We observed large inequality in the visual outcomes and principal causes of visual impairment after cataract surgery among different countries and regions. Structured quality control and enhancement programmes are needed to improve the outcomes of cataract surgery and reduce inequality.

Retrospective analysis of cataract surgery outcomes in China from 2009 to 2018: from a national registry system data

OBJECTIVE

To evaluate patients' benefits after cataract surgery and to form recommendations for Chinese national health policy decision makers and administration departments based on the quality of cataract treatments.

METHOD

An observational study based on real-world data source from the National Cataract Recovery Surgery Information Registration and Reporting System.

RESULTS

A total of 14 157 463 original records were reported from 1 July 2009 to 31 December 2018. The factors that influenced the 3-day postsurgical best-corrected visual acuity (BCVA), the primary outcome, were analysed by logistic regression analysis. We found that a history of hypertension (OR=0.916) or diabetes (OR=0.912), presurgical pupil abnormality (OR=0.571) and high intraocular pressure (OR=0.578) were harmful to the postsurgical BCVA improvement (BCVA ≥6/20), while male sex (OR=1.113), better presurgical BCVA level (OR=5.996 for ≥6/12-<6/7.5 and OR=2.610 for >6/60-<6/12 taken ≤6/60 as reference), age-related cataract (OR=1.825) and intraocular lens implantation (OR=1.886) were statistically beneficial to the postsurgical BCVA improvement. Compared with extracapsular cataract extraction (ECCE) with large incision, the ECCE with small incision (OR value=1.810) and the phacoemulsification (OR=1.420) significantly improved the benefit probability.

CONCLUSION

ECCE with small incision has comparable effects on postsurgical BCVA improvement of phacoemulsification. Therefore, ECCE could be an alternative cataract surgical treatment in economically underdeveloped areas in China, provided the surgeons are adequately trained.

Epidemiology, health policy and public health implications of visual impairment and age-related eye diseases in mainland China

The prevalence of visual impairment (VI) and age-related eye diseases has increased dramatically with the growing aging population in mainland China. However, there is limited comprehensive evidence on the progress of ophthalmic epidemiological research in mainland China to enhance our awareness of the prevention of eye diseases to inform public health policy. Here, we conducted a literature review of the population-based epidemiology of VI and age-related eye diseases in mainland China from the 1st of January 1946 to the 20th of October 2021. No language restrictions were applied. There was significant demographic and geographic variation in the epidemic of VI and age-related eye diseases. There are several factors known to be correlated to VI and age-related eye diseases, including age, gender, family history, lifestyle, biological factors, and environmental exposures; however, evidence relating to genetic predisposition remains unclear. In addition, posterior segment eye diseases, including age-related macular degeneration and diabetic retinopathy, are amongst the major causes of irreversible visual impairments in the senile Chinese population. There remains a significant prevention gap, with only a few individuals showing awareness and achieving optimal medical care with regards to age-related eye diseases. Multiple challenges and obstacles need to be overcome, including the accelerated aging of the Chinese population, the lack of structured care delivery in many underdeveloped regions, and unequal access to care. Despite the progress to date, there are few well-conducted multi-center population-based studies following a single protocol in mainland China, which findings can hopefully provide valuable cues for governmental decision-making and assist in addressing and halting the incidence of VI and age-related eye diseases in China.

Thicker Retinal Nerve Fiber Layer with Age among Schoolchildren: The Hong Kong Children Eye Study

This study aims to investigate the effect of age on the peripapillary retinal nerve fiber layer (p-RNFL) thickness among schoolchildren. A total of 4034 children aged 6–8 years old received comprehensive ophthalmological examinations. p-RNFL thickness was measured from a circular scan (⌀ = 3.4 mm) captured using spectral-domain optical coherence tomography (SD-OCT). Associations between p-RNFL thickness with ocular and systemic factors were determined by multivariate linear regression after adjusting potential confounders using generalized estimating equations (GEE). The mean global p-RNFL thickness was 106.60 ± 9.41 μm (range: 72 to 171 μm) in the right eyes, 105.99 ± 9.30 μm (range: 76 to 163 μm) in the left eyes, and 106.29 ± 9.36 μm (range: 72 to 171 μm) across both eyes. Age was positively correlated with p-RNFL after adjusting for axial length (AL) and confounding factors (β = 0.509; p = 0.001). Upon multivariable analysis, AL was positively associated with temporal p-RNFL thickness (β = 3.186, p < 0.001) but negatively with non-temporal p-RNFL thickness (β = (10.003, −2.294), p < 0.001). Sectoral p-RNFL was the thickest in the inferior temporal region (155.12 ± 19.42 μm, range 68 to 271 μm), followed by the superior temporal region (154.67 ± 19.99 μm, range 32 to 177 μm). To conclude, p-RNFL increased significantly with older age among children 6 to 8 years old in a converse trend compared to adults. Our results provide a reference for interpreting OCT information in children and suggest that stable p-RNFL thickness may not indicate a stable disease status in pediatric patients due to the age effects.

Prevalence of visual impairment among older Chinese population: A systematic review and meta-analysis

Background

To evaluate the prevalence of visual impairment (VI) among elderly Chinese population.

Methods

All population-based studies on VI prevalence among elderly Chinese populations were searched and only studies with clear definitions of diagnosis were selected. Meta-analysis methods were used to estimate the pooled prevalence and its 95% confidence interval (95%CI) of moderate and severe visual impairment (MSVI) and blindness both by presenting visual acuity (PVA) and best corrected visual acuity (BCVA). Subgroup analysis of gender, district, geographical location, age, education level and examined year were also conducted.

Results

72 studies with 465 039 individuals were included and analyzed. Using PVA, the pooled prevalence of MSVI is 10.9% (95% CI = 9.4%-12.6%) and blindness is 2.2% (95% CI = 1.8%-2.8%), while prevalence of MSVI and blindness by BCVA was 5.4% (95% CI = 4.6%-6.2%) and 2.2% (95% CI = 1.9%-2.5%), respectively. Females, rural residents, older age and lower educational level were risk factors for MSVI and blindness.

Conclusions

VI causes a great health burden among Chinese populations, particularly affecting female subjects, subjects dwelling in rural area, older subjects and subjects with lower educational level.

Blindness and Visual Impairment Situation in Indonesia Based on Rapid Assessment of Avoidable Blindness Surveys in 15 Provinces

Purpose: To report the latest data on blindness and visual impairment (VI) in Indonesia.Methods: Rapid Assessment of Avoidable Blindness (RAAB) surveys were done in 15 provinces in Indonesia between 2013 and 2017. The population of the study was people aged 50 +. In each province, the required number of clusters was selected with a probability proportionately to size. A weighted average analysis for prevalence, causes of visual impairment, and cataract surgical coverage (CSC) estimated the values of the country.Results: The prevalence of blindness in East Java was the highest at 4.4% (95% CI: 3.1-5.6%), followed by Nusa Tenggara Barat (NTB) at 4.0% (95% CI: 3.0-5.1%) and South Sumatra at 3.4% (95% CI: 2.4-4.4%). In number, blindness among people aged 50+ in East Java was the highest at 371,599, followed by West Java at 180,666 and Central Java at 176,977. Untreated cataract was the commonest cause of blindness in all provinces (range: 71.7% to 95.5%). CSC_person<3/60 and CSC_person<6/60 in Bali were the highest at 81.3% and 72.4%, respectively. Indonesia countrywide prevalence of blindness was 3.0%. The total number of people with VI (PVA less than 6/18 in the better eye) in Indonesia was 8,019,427, consisting of 1,654,595 of blindness and 6,364,832 of moderate and severe VI.Conclusion: The burden of blindness in Indonesia is high, and untreated cataract contributes the most. There is an urgent need to increase cataract surgical coverage by providing better access to cataract surgery services for all people in need.

Impact of cataract screening integrated into establishment of resident health record on surgical output in a rural area of south China

Background

Strategy establishment for improving the efficiency and sustainability of cataract surgical output is important for eye health program. The aim of this study is to assess the three-year output of a novel cataract screening model integrated into establishment of resident health record in a rural area of south China.

Methods

A novel cataract screening model which combined private hospital screening and annual health examinations for establishing resident health record from January 2015 to December 2017 was implemented in an eye hospital in Zhaoqing, Guangdong, China. Demographic information and cataract surgery rate were recorded. A subgroup of patients who underwent cataract surgery were surveyed by customized questionnaire to determine the accessibility to eye-care services and barriers to cataract surgery.

Results

A total of 172,814 people aged ≥50 years in Zhaoqing were screened and 56,292 (32.57%) people were diagnosed with age-related cataract, among whom 18,422 (10.66%) with a best corrected visual acuity (BCVA) less than 20/63 were recommended for cataract surgery. Surgery was performed on 11,105 (60.28%) recommended patients. After the introduction of this screening model, the cataract surgical rate (CSR) in this area dramatically increased to 2,739/million/y (by 1.8 folds) in 2015 and 3,678/million/y (by 2.4 folds) in 2017, compared with that in 2014 (1,520/million/y). Accessibility to eye-care service was improved, and the main reason for not receiving cataract surgery changed from misconception of cataract to having good vision in the fellow eye after 3 years of screening.

Conclusions

This study documented the benefit of a novel cataract screening model integrated into establishment of resident health record in rural China, which may serve as a cost-effective, practicable, and sustainable strategy to disseminate cataract knowledge and eliminate cataract blindness.

Willingness to pay for cataract surgery in baiyin district, northwestern China

PURPOSE

To investigate willingness to pay for cataract surgery, and its associations, in Northwestern China.

METHODS

Four hundred thirty-eight persons aged 50 years and above, diagnosed with cataract indicated for surgery, identified in an outreach screening program were included. Subjects were offered a willingness-to-pay interview for the maximal amount that the subjects would be willing to pay for a cataract surgery. Age, gender, literacy, education level, occupation, and annual household income were recorded.

RESULTS

Among 328 (74.9%) subjects who completed the interview, 197 (60.1%) participants were willing to pay something for the cataract surgery (mean, 902.9 ± 856.7 renminbi[RMB], [US$ 145 ± 137]; median, 500RMB, US$ 78). Individuals with presenting visual acuity (PVA) in the worse eye ≤6/60 (OR: 2.1, 95% CI: 1.3-3.2) and a high annual household incomes (OR: 2.0, 95% CI: 0.9-4.6) were likely to be willing to pay for the surgery, as revealed in the regression models. Willingness to pay any amount for cataract surgery was more likely among literate persons (OR: 1.5, 95% CI: 1.0-2.4) and persons with non-agricultural occupation (OR: 1.8, 95% CI: 1.0-3.2).

CONCLUSIONS

The amount that subjects were willing to pay is significantly less than the current cost of cataract surgery (5000 RMB, US$320) in the area. Providing low-cost cataract surgery to patients in a financially sustainable manner is important to increase uptake of cataract surgery among rural residents in Northwest China.

Diagnostic Accuracy of Rapid Assessment of Avoidable Blindness: A Population-based Assessment

OBJECTIVES

To evaluate the diagnostic accuracy of rapid assessment of avoidable blindness (RAAB).

DESIGN

Population-based diagnostic accuracy study.

METHODS

A total of 2145 (95.3%, 2145/2250) subjects aged 50 years and older who participated in the RAAB survey were included. All the recruited participants underwent ophthalmic examination according to the RAAB protocol and then were reexamined 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 logMAR charts, refraction, slit-lamp biomicroscopy, and dilated fundal examination with a binocular indirect ophthalmoscope. Blindness and economic blindness were defined as VA in the better-seeing eye <3/60 and <6/60, respectively. Visual impairment (VI) was defined as VA <6/18 in the better eye. The primary cause of blindness and VI was defined according to the cause of VI in the participant's better eye.

MAIN OUTCOME MEASURES

The sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), and area under the curve (AUC) of receiver operating characteristics of RAAB for detection of blindness and the principal causes of VI.

RESULTS

A total of 1816 subjects (84.7%), including 686 men (37.8%) and 1130 women (62.2%), underwent ophthalmic examination in the mobile eye clinic. The mean (±standard deviation) age was 64.4 ± 9.6 years. The sensitivities, specificities, AUC, PLR, and NLR of RAAB were 90.3%, 99.3%, 0.948, 124.0, and 0.10, respectively, for detection of blindness (presenting visual acuity, PVA <3/60); 89.5%, 98.7%, 0.940, 69.2, and 0.11, respectively, for detection of economic blindness (PVA <6/60); and 90.3%, 97.7%, 0.940, 38.7, and 0.10, respectively, for detection of VI (PVA <6/18). The sensitivities, specificities, AUC, PLR, and NLR were 90.5%, 98.1%, 0.943, 48.1, and 0.10; and 60.4%, 98.7%, 0.796, 46.4, and 0.40 for detection of VI (PVA <6/18) owing to cataract and refractive error, respectively.

CONCLUSION

The diagnostic performances of RAAB were high for detecting the prevalence of blindness, VI, and VI owing to cataract.

Prevalence and service assessment of cataract in Tibetan areas of Sichuan Province, China: population-based study

OBJECTIVES

To assess the prevalence of visual impairment (VI) and blindness (BL) due to cataract and cataract surgical outcomes in remote dispersed and high-altitude Tibetan areas of China.

DESIGN AND SETTING

A cross-sectional study was conducted among people aged 50 and above in Tibetan Autonomous Prefecture of Kandze (TAPK), China, in 2017. The Rapid Assessment of Avoidable Blindness protocol was followed.

PARTICIPANTS

Of 5000 eligible participants, 4764 were examined (response rate 95.3%).

PRIMARY AND SECONDARY OUTCOME MEASURES

Cataract VI was defined as lens opacity at visual acuity (VA) levels of <3/60 (Blindness (BL)), ≥3/60 and <6/60 (severe visual impairment (SVI)), ≥6/60 and <6/18 (moderate visual impairment (MVI)), ≥6/18 and <6/12 (early visual impairment (EVI)).

RESULTS

The estimated prevalence of cataract BL was 0.61% (95% CI 0.42 to 0.87). With best corrected VA, the estimated prevalence of SVI from cataract was 0.86% (95% CI 0.63 to 1.17); MVI was 2.39% (95% CI 2.00 to 2.87) and EVI was 5.21% (95% CI 4.61 to 5.87). Women in TAPK had a significantly higher prevalence of cataract BL (0.82%, 95% CI 0.54 to 2.15) than men (0.34%, 95% CI 0.16 to 0.70). Women had lower cataract surgical coverage (CSC) by eyes (60.8%, 95% CI 55.5 to 65.8) compared with men (70.1%; 95% CI 63.7 to 75.7). The prevalence of cataract BL was higher among Tibetan (2.28%; 95% CI 1.98 to 2.62) than Han Chinese (1.01%%; 95% CI 0.54% to 1.87%). Overall CSC by person with BL (by better eye) was 82.0% (95% CI 75.2 to 87.6). Among cataract-operated participants, 71.2% had VA equal to or better than 6/18.

CONCLUSIONS

The study detected a low prevalence of VI and BL due to cataract with high CSC in the study area compared with many other places in China. Further actions should be taken to improve cataract surgical outcome.

Phacoemulsification Cataract Surgery Affects the Discriminative Capacity of Iris Pattern Recognition

Cataract is a common ophthalmic disorder and the leading cause of blindness worldwide. While cataract is cured via surgical procedures, its impact on iris based biometric recognition has not been effectively studied. The key objective of this research is to assess the effect of cataract surgery on the iris texture pattern as a means of personal authentication. We prepare and release the IIITD Cataract Surgery Database (CaSD) captured from 132 cataract patients using three commercial iris sensors. A non-comparative non-randomized cohort study is performed on the iris texture patterns in CaSD and authentication performance is studied using three biometric recognition systems. Performance is lower when matching pre-operative images to post-operative images (74.69 ± 9.77%) as compared to matching pre-operative images to pre-operative images (93.42 ± 1.76%). 100% recognition performance is observed on a control-group of healthy irises from 68 subjects. Authentication performance improves if cataract affected subjects are re-enrolled in the system, though re-enrollment does not ensure performance at par with pre-operative scenarios (86.67 ± 5.64%). The results indicate that cataract surgery affects the discriminative nature of the iris texture pattern. This finding raises concerns about the reliability of iris-based biometric recognition systems in the context of subjects undergoing cataract surgery.

Prevalence of visual impairment and its association with vision-related quality of life among elderly persons in a resettlement colony of Delhi

Background:

The population of India is ageing. The number and percentage of elderly persons is increasing. Visual impairment is common among elderly persons and affects their vision-related quality of life. The objective of this study was to estimate the prevalence of visual impairment among elderly persons aged 60 years and above residing in a resettlement colony of Delhi and study its association with socio-demographic variables and vision-related quality of life.

Methods:

A total of 604 elderly participants were selected by simple random sampling. House-to-house visit was done, and a self-developed pre-tested semi-structured interview schedule was used to collect socio-demographic information. Visual acuity was measured using Snellen's chart, and distant direct ophthalmoscopy was done to diagnose cataract. Vision-related quality of life was assessed by Indian Vision Function Questionnaire-33 (IND-VFQ-33).

Results:

Of the 604 participants, 555 (91.9%) were available for interview. The prevalence of visual impairment was 24.5% (95% CI: 20.9% - 28.1%). Cataract was the leading cause of visual impairment (50.7%), followed by uncorrected refractive error (36.8%). Illiteracy (aOR: 3.49, 1.37-8.87), economic dependence on family members (aOR: 1.92, 1.04 – 3.54), not currently working (aOR: 1.89, 1.20-2.98) and chewing of tobacco products (aOR: 2.56, 1.48-4.42) were significantly associated with visual impairment among study participants. Vison-related quality of life was worse among those with visual impairment.

Conclusion:

Burden of visual impairment is high among elderly persons living in urban resettlement colonies. It is largely avoidable. Eye-care services should be accessible and affordable to them.

Central corneal thickness changes following manual small incision cataract surgery versus phacoemulsification for white cataract

Aim: To assess the central corneal thickness (CCT) and endothelial cell loss after manual small-incision cataract surgery and phacoemulsification in patients with white cataract. Material and methods: This is a comparative, prospective, non-randomized study on 42 patients with white cataract, who underwent cataract surgery. The patients were divided into manual small-incision cataract surgery (21 eyes, MSICS group) and phacoemulsification cataract surgery group (21 eyes, phaco group). The endothelial cell density (ECD), central cornea thickness (CCT), and corrected distance visual acuity (CDVA) were evaluated at 1 day, 1 week, 4 weeks, and 3 months postoperatively. The results of 20 cases of nuclear sclerosis grade II-III (LOCS III) who underwent phacoemulsification by the same surgeon were also compared. Propensity scoring was used to adjust for confounding by selection bias. Results: The CCT increased after surgery in both groups. The thickness was greater in the phaco group on first day postoperatively (73 µ increase in MSICS group and 138 µ in phaco group, p=0.008) and it returned to preoperative levels 1 month postoperatively. The endothelial cell loss was lower in the MSICS group at 3 months postoperatively (11.8% in MSICS group and 15.8% in phaco group, p=0.111). The CDVA was not different in both groups at 1 week and 4 weeks postoperatively (p>0.05). Conclusions: Manual small-incision cataract surgery for white cataract provided less central corneal thickness changes compared to conventional phacoemulsification. Abbreviations: CCT = central corneal thickness; ECD = endothelial cell density; CDVA = corrected distance visual acuity; APT = absolute phacoemulsification time; EPT = effective phacoemulsification time; MSICS = Manual small-incision cataract surgery in white cataract; Phaco II = Phacoemulsification in white cataract; Phaco I = phacoemulsification in NS 2 + Cataract; Phaco = Phacoemulsification in white cataract; APACRS = Asia-Pacific Association of Cataract and Refractive Surgeons.

Blindness and eye disease in a Tibetan region of China: findings from a Rapid Assessment of Avoidable Blindness survey

Introduction

The only population-based survey of blindness and visual impairment of a Tibetan population was conducted in the Tibet Autonomous Region in 1999.

Methods and analysis

The Rapid Assessment of Avoidable Blindness methodology was used to conduct a survey of Kandze Tibetan Autonomous Prefecture, Sichuan Province of China in the Fall 2017. Using the 2010 census, 100 clusters of 50 participants aged 50 years or older were randomly sampled using probability proportionate to size.

Results

Among the 5000 people enumerated, 4763 were examined (95.3% response). The age-adjusted and sex-adjusted prevalence of blindness, severe visual impairment, moderate visual impairment and early visual impairment (EVI) were 1.6% (95% CI: 1.08 to 2.38)), 0.9% (95% CI:0.7 to 1.5), 5.1% (95% CI:4.4 to 5.7), and 7.45% (95% CI:6.67 to 8.2), respectively. The prevalence of blindness among Tibetans was significantly higher than that among Han Chinese (2.2% (95% CI:1.8 to 2.6) and 0.6 (95% CI:0.2 to 1.7), respectively, p<0.05). Women bore a significant excess burden of EVI compared with men (8.5% (95% CI:7.5 to 9.6) and 6.1% (95% CI:5.1 to 7.2), respectively, p<0.05). Cataract was the primary cause of blindness (39.4%) followed by macular degeneration (10.6%) and corneal opacity (5.3%).

Conclusion

Blindness and visual impairment in Kandze Tibetan Autonomous Prefecture is substantially less than an earlier study of a Tibetan region and now resembles other regions of China. About 58% of blindness and 67% of SVIwere avoidable, primarily by providing cataract services. Eighty-three percent of EVI was avoidable by providing refractice services throughout the region.