Changing trends of blindness, visual impairment and cataract surgery in Bhutan: 2009-2018

Mapping gaps and exploring impairment and disability prevalence in South Asian (SAARC) countries: a scoping review

Despite the considerable health and economic burden of disability in the South Asian (SA) region, there is limited evidence of impairments and disabilities prevalence and the need for Assistive Technologies (ATs). This scoping review aims to synthesise the evidence of the impairments and disabilities in SA countries. This review followed Arksey and O'Malley's methodological framework. EBSCOhost, EMBASE, PubMed, and Web of Science databases were searched for original research articles from SA countries. In this study, impairment and disability refer to functional limitations restricting individuals from performing activities, including visual, hearing, speaking, cognitive, mobility, and self-care difficulties. The review included full-text, English-language articles addressing any impairment and disability, without restrictions on publication date. This review identified 105 articles distributed over the six impairment and disability domains: visual, hearing, mobility, self-care, speaking, and cognitive. Most evidence originated from India (50.5%) and focused on visual impairments (53.3%). The review identified that heterogeneity in methodologies, case identification definitions, and study settings contributed to variations in prevalence estimation and restricted the comparability within and across countries. Besides, the uneven distribution of studies across countries suggests varying inclinations of countries toward specific impairment and disability domains. The review identified variations in prevalence due to differences in methodologies, definitions, and contexts. The review also identified the uneven distribution of studies, limited evidence on ATs, reliance on self-reported data, and lack of nationally representative research. Future research should use standardised case identification and evidence-based approaches to enhance comparability and minimise response biases.

Prevalence and causes of blindness and vision impairment among people 50 years and older in Nepal: A national Rapid Assessment of Avoidable Blindness survey

PURPOSE

To determine the prevalence and causes of blindness and vision impairment among people 50 years and older in Nepal.

METHODS

We conducted seven provincial-level Rapid Assessment of Avoidable Blindness (RAAB) cross-sectional, population-based surveys between 2018-2021. Provincial prevalence estimates were weighted to give nationally representative estimates. Sampling, enumeration, and examination of the population 50 years and older were done at the province level following standard RAAB protocol.

RESULTS

Across seven surveys, we enrolled 33,228 individuals, of whom 32,565 were examined (response rate 98%). Females (n = 17,935) made up 55% of the sample. The age-sex-province weighted national prevalence of blindness (better eye presenting visual acuity <3/60) was 1.1% (95% confidence interval [CI] 1.0-1.2%), and any vision impairment <6/12 was 20.7% (95% CI 19.9-21.5%). The prevalence of blindness was higher in women than men (1.3% [95% CI 1.1-1.5%] vs 0.9% [95% CI 0.7-1.0%]). Age-sex weighted blindness prevalence was highest in Lumbini Province (1.8% [95% CI 1.3-2.2%]) and lowest in Bagmati Province (0.7% [95% CI 0.4-0.9%]) and Sudurpaschim Province (0.7% [95% CI 0.4-0.9%]). Cataract (65.2%) was the leading cause of blindness in our sample, followed by corneal opacity (6.4%), glaucoma (5.8%) and age-related macular degeneration (5.3%). Other posterior segment diseases accounted for 8.4% of cases. Cataract was also the leading cause of severe vision impairment (83.9%) and moderate vision impairment (66.8%), while refractive error was the leading cause of mild vision impairment (66.5%).

CONCLUSION

The prevalence of blindness was higher among women than men and varied by province. The Lumbini and Madesh Provinces in the Terai (plains) region had higher prevalence of blindness than elsewhere. Cataract was the leading cause of blindness, severe vision impairment and moderate vision impairment while refractive error was the leading cause of mild vision impairment.

Prevalence of visual impairment and its causes in adults aged 50 years and older: Estimates from the National Eye Surveys in Malaysia

BACKGROUND

Population surveys are necessary to measure a community's eye care needs. We conducted simultaneous surveys in two regions in Malaysia in 2023 to estimate the prevalence of blindness and/or visual impairment (VI), identify its main causes, and compare the results with the survey in 2014.

METHODS

The surveys were simultaneously done in Eastern and Sarawak administrative regions using the Rapid Assessment of Avoidable Blindness (RAAB) technique. It involved a multistage cluster sampling method, each cluster comprising 50 residents aged 50 years and older. The prevalence of blindness and/or visual impairment (blindness, severe, moderate, and early) and its primary cause were determined through a visual acuity test and eye examination with a hand-held ophthalmoscope. Results were compared with the previous survey in 2014.

RESULTS

A total of 10,184 subjects were enumerated, and 9,709 were examined (94.5% and 96.2% responses for Eastern and Sarawak, respectively). The prevalence of blindness and severe VI appeared lower than the previous survey. For blindness: Eastern 1.4%, 95%CI (0.9, 1.9) to 0.8%, 95%CI (0.5, 1.1) and Sarawak: 1.6% 95%CI (1.0, 2.1) to 0.6%, 95%CI (0.3, 0.9). For severe VI: Eastern 1.2%, 95%CI (0.8, 1.7) to 0.9%, 95%CI (0.6, 1.1) and Sarawak 1.1% 95%CI (0.6, 1.6) to 0.9%, 95% CI(0.6, 1.2). The main cause of blindness was untreated cataracts: 77.3% (Eastern) and 75.0% (Sarawak). Diabetic retinopathy was the 2nd main cause of blindness for Eastern at 9.1%, but it only caused early to severe VI in Sarawak.

CONCLUSION

The prevalence of blindness and severe VI were lower than in the previous survey. It could have been attributed to a community cataract program implemented soon after the survey in 2014. However, more efforts are needed to address the high percentage of avoidable blindness within both regions.

Trends in the prevalence of vision impairment among the oldest-old Chinese population from 1998 to 2018

Background

Vision impairment has become a prominent public health issue worldwide. However, little is known about vision impairment prevalence trends among the oldest-old adults in China. This study aimed to examine 20-year trends in the prevalence of vision impairment among the oldest-old Chinese adults and explore the contributions of sociodemographic variables, health behaviours, and chronic conditions to the trends.

Methods

This retrospective longitudinal study used data from the Chinese Longitudinal Healthy Longevity Survey during 1998-2018. A total of 45 849 participants aged ≥80 years at study entry were included. Vision impairment was assessed by an adapted Landolt-C chart at each wave. We examined unadjusted and adjusted nonlinear trends using generalized estimating equation models incorporating a natural cubic spline. We conducted linear regression models to estimate absolute annual prevalence changes and determine the contributions of sociodemographic variables, health behaviours, and chronic conditions to the trends.

Results

The fully adjusted prevalence doubled from 5.5% (95% confidence interval (CI) = 5.1%-6.0%) in 1998 to 10.7% (95% CI = 9.9%-11.5%) in 2011 and slightly increased to 11.1% (95% CI = 10.3%-12.0%) in 2018 among the oldest-old Chinese population. Glaucoma, cataracts, cognitive impairment, hearing impairment, and urban residence were significant contributors to changes in vision impairment prevalence during 1998-2018. Differences in vision impairment prevalence associated with glaucoma and cataracts narrowed since 2005. Disparities in the trends among cognitively impaired and unimpaired older adults remained unchanged over time. Similar results were observed in older people with and without hearing impairment.

Conclusions

Vision impairment prevalence among the oldest-old Chinese population increased from 1998 to 2011 and remained stable from 2011 to 2018. Future work is needed to improve the prevention and management of chronic diseases associated with vision impairment to reduce its prevalence.

Tribal Odisha Eye Disease Study (TOES). Report # 10. Disability inclusive eye health survey in a tribal district (Rayagada) in Odisha, India

Purpose:

To estimate seeing and other disabilities in a population cohort in a tribal district, Rayagada, in the Indian state of Orissa.

Methods:

A door-to-door survey was conducted to identify the disabilities. The vision was measured at the residence of the subject, and other disabilities were documented from the history obtained from the subject/household/neighbor. All people with seeing disabilities were reexamined in the community eye center (primary or secondary), and required treatment was given at no cost to the patients. People with other disabilities were transported to the public health facility for appropriate care and disability certification. The results were compared with the 2011 national census data.

Results:

A total of 147,699 people were enumerated, and 106,339 (72%) were examined over one year period, 2016–17. In this cohort, 47.3% (n = 50,320) were male and 27.5% (n = 29,215) were 40 years or older. We recorded systemic disease in 0.6% (n = 689) people; hypertension was two times higher than diabetes mellitus. Disability was identified in 2.8% (n = 3022). Common disabilities were seeing (46.7%; n = 1411), hearing (36.8%; n = 1112), mobility (10.4%; n = 315), and mental retardation (3.2%; n = 98). Dual sensory disability (seeing and hearing) was seen in 6.4% (n = 251), and it was higher in the older age group. Seeing and hearing disabilities were higher than the 2011 state (P =< 0.001) and national (P =< 0.001) disability census.

Conclusion:

The first population-based survey in Rayagada, Odisha (India) in 2017 showed a higher proportion of people with seeing and hearing disabilities. It calls for an appropriate service strategy.

Common causes of visual impairment in the elderly

Background

Aging is not a disease; rather, it is a process. As people age, visual impairment (VI) becomes more common. In 2010, the overall prevalence rate of vision impairment in all races was 25.66% in individuals aged ≥ 80 years, according to the estimate of the National Eye Institute at the National Institutes of Health. This review aimed to address the common causes of VI in the elderly.

Methods

In this narrative review, an electronic search of the PubMed/MEDLINE database was conducted using "visual impairment" and "elderly" for the period between January 2010 and April 2021, to include randomized clinical trials and observational studies concerning VI in the elderly. The selected time period was chosen to provide an updated review.

Results

The search yielded 2955 articles published over the period of more than 11 years. The relevant randomized clinical trials or observational studies were included and reviewed. Cataracts, refractive errors, open-angle glaucoma, age-related macular degeneration, and diabetic retinopathy were the most common age-related ocular disorders leading to VI if untreated in the elderly. The loss of visual acuity can adversely affect quality of life in the elderly. Difficulty with activities of daily living related to VI can lead to social isolation, depression, and anxiety. Loss of vision in the elderly is linked to an increased risk of falls, hip fracture, depression, and poor quality of life.

Conclusions

The most common causes of VI in the elderly are cataracts and refractive errors. VI in most ocular diseases is more prevalent in women than in men due to longer lifespan. The overall prevalence of the main causes of VI in the elderly is expected to increase; therefore, health policymakers should consider this when planning for the health-enhancement program of the population.

Corneal Blindness in Asia: A Systematic Review and Meta-Analysis to Identify Challenges and Opportunities

PURPOSE

To describe the causes and prevalence of moderate-to-severe visual impairment (MSVI) and blindness from corneal diseases, as well as corneal transplantation across Asia.

METHODS

A meta-analysis of the published literature to identify population-based surveys conducted from 2008 to 2019 in 22 Asian countries regarding the prevalence and causes of MSVI and blindness from corneal disease, and a review of national corneal transplant data and eye bank statistics.

RESULTS

A total of 5307 records were screened to identify 57 reports that were used to estimate a prevalence of MSVI and blindness caused by corneal diseases in Asia of 0.38% (95% confidence interval, 0.29%-0.48%). The most frequent corneal diseases were infectious keratitis, trauma, and pseudophakic bullous keratopathy. As expected, these represented the most common indications for corneal transplantation, although the percentages in each country differed based on the level of economic development, with pseudophakic bullous keratopathy being the most common indication in countries with higher gross national income per capita. Despite this, endothelial keratoplasty is not the most commonly performed form of corneal transplantation in any Asian country and represents only a small percentage of keratoplasty procedures performed in most countries.

CONCLUSIONS

The prevalence of MSVI and blindness from corneal disease in Asia is approximately 0.4%, with a nearly 20-fold difference in the national prevalence across the region. The indications for keratoplasty, reflective of the causes of corneal dysfunction, also vary, more so according to the gross national income than to geographic location, and only a few Asian countries have rates of corneal transplantation above international means.

Development of Diabetic retinopathy screening guidelines in South-East Asia region using the context, challenges, and future technology

Objective: To formulate guidelines for screening of diabetic retinopathy (DR) for the World Health Organization (WHO) South-East Asia Region (SEAR) aligned with the current infrastructure and human resources for health (HRH).Design: A consultative group discussion of technical experts of the International Agency for the Prevention of Blindness (IAPB) from SEAR.Participants: IAPB country chairs and DR technical experts from SEAR countries.Methods: Data related to DR in SEAR was collected from published literature on available DM and DR guidelines and the participating experts. The 10 SEAR countries (the Democratic Republic of Korea was not included for lack of sufficient data) were divided into 3 resource levels (low, medium, and high) based on gross national income/per capita, cataract service indicators (cataract surgical rate and cataract surgical service), current infrastructure and available HRH. Two countries each were assigned to low (Myanmar, Timor-Leste) and high resource (India, Thailand) levels, and the remaining 6 countries (Bangladesh, Bhutan, Indonesia, Maldives, Nepal, Sri Lanka) were assigned the medium resource level. The DR care system was divided into 3 levels of care (essential, recommended, and desirable) and 3 levels of service delivery (primary, secondary, and tertiary).Main outcome measures: Primary, secondary, and tertiary level guidelines for screening of DRResults: Nine WHO SEAR countries participated in the formulation of the new country-specific DR screening guidelines. The DR screening recommendations were: advocacy at the community level, visual acuity measurement, and non-mydriatic fundus photography at the primary level, comprehensive eye examination and retinal laser at the secondary level, and intravitreal therapy and vitrectomy at the tertiary level. The systemic care of DM and hypertension are recommended at all levels commiserating with their care capabilities.Conclusions: The DR guidelines for the SEAR region are the first region-specific and resource-aligned recommendations for comprehensive DR care in each country of the region. In the future, the new technological advances in retinal camera technology, teleophthalmology, and artificial intelligence should be included within the structure of the public DR care system.

Surgical coverage of cataract in a rural area of north India: A cross-sectional study

Background:

India has the highest number of blind people globally, unoperated cataract being the most common cause of blindness and low vision. Although safe and effective cataract surgical techniques are available, the cataract burden continues to increase annually, due to the backlog of patients to be operated upon, and a growing number of cataract cases due to increased life expectancy.

Aim:

To assess cataract surgical coverage (CSC) in a rural area of north India.

Methods:

A population-based cross-sectional study of CSC among adults (40 years and above) was carried out in two villages of a block in north India using a predesigned questionnaire, visual acuity assessment, and distant direct ophthalmoscopy. Based on the data obtained, CSC (VA <6/60) for both “persons” as well as “eyes” was calculated.

Results:

Overall, CSC (persons) of 43.20% was observed, 29.31% coverage among persons with unilateral cataract and 50.45% among persons with bilateral cataract while CSC (eyes) was found to be 37.14%, being significantly higher (43.56%) among females compared to males (28.21%) (P = 0.012). Around 50% of cataract surgeries were performed in private facilities, 41.35% in government facilities, and rest 8.65% in eye camps. Nearly 90.38% were implanted intraocular lens and 9.62% were non-intraocular lens surgeries.

Conclusions:

Surgical needs for cataract are currently not being met effectively. Reasons for inadequate cataract surgical services need to be sought and addressed to improve the uptake of existing services. Further, reasons for underutilization of government hospitals for cataract surgeries need to be examined.

Pattern of vitreo-retinal diseases at the national referral hospital in Bhutan: a retrospective, hospital-based study

BACKGROUND

Knowing the pattern and presentation of the diseases is critical for management strategies. To inform eye-care policy we quantified the pattern of vitreo-retinal (VR) diseases presenting at the national referral hospital in Bhutan.

METHODS

We reviewed all new patients over three years from the retinal clinic of the Jigme Dorji Wangchuck National Referral Hospital. Demographic data, presenting complaints and duration, treatment history, associated systemic diseases, diagnostic procedures performed, and final diagnoses were quantified. Comparisons of the expected and observed frequency of gender used Chi-squared tests. We applied a sampling with replacement based bootstrap analysis (10,000 cycles) to estimate the population means and the standard errors of the means and standard error of the 10th, 25th, 50th, 75th and 90th percentiles of the ages of the males and females within 20-year cohorts. We then applied t-tests employing the estimated means and standard errors. The 2913 subjects insured that the bootstrap estimates were statistically conservative.

RESULTS

The 2913 new cases were aged 47.2 ± 21.8 years. 1544 (53.0%) were males. Housewives (953, 32.7%) and farmers (648, 22.2%) were the commonest occupations. Poor vision (41.9%), screening for diabetic and hypertensive retinopathy (13.1%), referral (9.7%), sudden vision loss (9.3%), and trauma (8.0%) were the commonest presenting symptoms. Coexistent diabetes and hypertension were the most common associated systemic diseases. Haematological tests (blood sugar, HbA1c and lipid profile, 31.8%), OCT (27.4%), refraction (9.9%), B-scan (8.7%), fundus photography (8.0%) were the most commonly performed diagnostic tests. Hypertensive retinopathy (18.9%) was the commonest VR disease, followed by refractive errors referred for retinal evaluation (16.7%), diabetic retinopathy with macular oedema (15.8%), and AMD (11.0%). Retinal detachment was more prevalent in females (83 vs. 41, p = 0.007). Rare vision-threatening diseases like seasonal hyper-acute pan-uveitis also presented.

CONCLUSIONS

The developing VR service in Bhutan is challenged by the spectrum of diseases, limited human resources (e.g. one retinal surgeon during the study), and accessibility to tertiary eye-care services, all amidst difficult terrain. Sustained effort and robust coordination among the eye-care professionals, government and non-governmental organisations are critical for optimising VR services, especially as rates of diseases such as diabetes and hypertension grow.

Capacity building for universal eye health coverage in South East Asia beyond 2020

BACKGROUND

The World Report on Vision suggests that universal eye health coverage (UEHC) can be achieved through an integrated people-centered eye care (IPCEC) delivery. This study provides an estimation of capacity building of facilities and workforce to attain UEHC through IPCEC in South East Asia (SEA) beyond 2020.

METHODS

The data sources on the magnitude of blindness and visual impairment in the SEA region included reports of the Vision Loss Expert Group, most recent population-based studies from the member states and unpublished data from the study teams. The model is based on the estimated or projected population of the member states in 2020 and 2030.

RESULTS

Data from the ten member states of the World Health Organization (WHO) SEA show that the magnitude of blindness and moderate to severe visual impairment (MSVI) has decreased between 1990 and 2015, but still higher than global average. Cataract and uncorrected refractive errors were the common causes of blindness and MSVI, respectively. The estimated WHO SEA region share of world population is likely to increase from 38.39% in 2020 to 44.32% in 2030, and so also will be the visually impaired people. By adopting the IPCEC the WHO SEA countries would require at least 429,802 community workers, 164,784 allied ophthalmic personnel and 10,744 ophthalmologists in the public facilities in 2030.

CONCLUSION

In order to attain UEHC and use the IPCEC model, each country in the region should invest substantially more in structured eye care delivery and workforce.