Blindness, low vision and cataract surgery outcome among adults in Hohhot of Inner Mongolia: a Rapid Assessment of Avoidable Blindness (RAAB) study

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.

Causes of Blindness in the Adult Population in Somalia

Objectives

To evaluate the causes and frequency of blindness among the adult Somali population according to the World Health Organization (WHO) criteria.

Materials and Methods

The data of 2,605 patients over 18 years old who presented to our tertiary hospital in Mogadishu (the capital of Somalia) were evaluated. Patients with best corrected visual acuity of less than 3/60 in both eyes were categorized as bilaterally blind and those with best corrected visual acuity of less than 3/60 in one eye but 3/60 or better in the other eye were classified as monocularly blind, as per the WHO classification.

Results

Of 2,605 patients, 1,251 (48%) were female and 1,354 (52%) were male. Among these, 256 patients were determined to have blindness in one or both eyes and were included in the study. The patients ranged in age from 19 to 85, and the mean age was 52.4±14.6 years. The overall blindness rate in the Somali population was 9.8%. In the monocularly blind group, the most common factor was trauma complication (23.6%), followed by cataract (19%) and diabetic retinopathy (13.2%). In the bilaterally blind group, the most common factors were cataract (26.9%), diabetic retinopathy (21.1%), and glaucoma (15.4%).

Conclusion

Trauma is the leading cause of blindness due to the security conditions in the country. Establishing and increasing the number of free public health centers in Somalia can reduce the frequency of blindness.

Validity and feasibility of a self-administered home vision examination in Yueqing, China: a cross-sectional study

OBJECTIVE

To investigate the validity and feasibility of a self-administered home vision examination programme in China.

DESIGN

Cross-sectional study.

SETTING

Yueqing, China.

PARTICIPANTS

A two-stage convenience sampling procedure was used to randomly select 600 households from 30 communities participating in the Yueqing Eye Study (YES). The aim of YES is to encourage home-based vision screening, reporting of visual acuity (VA) annually through social media and encouraging people to attend follow-up clinic appointments as a way to improve eye care access for adults with VA ≤+0.5 log of the minimum angle of resolution (logMAR).

INTERVENTIONS

Household screeners (one per household) who tested other family members' VA completed a questionnaire on family structure, demographic information and knowledge about screening procedures. Other family members then underwent confirmatory VA testing by researchers.

OUTCOME MEASURES

The completion rate of home-based VA screening, its sensitivity and specificity were used to evaluate validity. Factors that determined whether families participated in the self-VA screening were used to evaluate feasibility.

RESULTS

345 (66%) of the 523 (87.2%) households with valid data form their home-based vision examinations also were retested by researchers. There was no statistically significant difference in scores on the family-administerd or researcher-administerd VA test (VA≤+0.5 logMAR, p=0.607; VA >+0.5 logMAR, p=0.612). The sensitivity and specificity of home-based vision screening were 80.5% (95% CI 70.2% to 86.9%) and 95.1% (95% CI 92.6% to 96.8%), respectively. 14.7% (77/523) of tested respondents had VA ≤+0.5 logMAR. Predictors of performing home screening for VA remaining in regression models included higher economic status ('fair and above' vs 'poor': OR 1.74; 95% CI 1.08 to 2.76; p=0.022), age (<45 years vs ≥45 years: OR 0.46; 95% CI 0.25 to 0.85; p=0.014) and living in a nuclear (OR 5.17; 95% CI 2.86 to 9.36; p<0.001) or extended family (OR 8.37; 95% CI 4.93 to 14.20; p<0.001).

CONCLUSION

Self-administered home vision screening is reliable and highly accepted by Chinese adults.

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.