A conversation with leading epidemiologists about the status of vision loss in the seven super-regions of the world.
In this article we speak with Vision Loss Expert (VLEG) members Professors Ningli Wang and Robert Casson about the status of vision loss in the South-East Asia, East Asia, and Oceania Region.
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What are the 3 key take away messages for policy makers about vision loss in your region?
NW: Improving the equity in eye care access is the key to gender equity. In Southeast Asia, East Asia and Oceania, the age-standardized prevalence of both blindness and moderate/severe vision impairment is higher in females. In fact, globally speaking, 55% of people with vision loss are women and girls, and women are 12% more likely to have vision loss than men.
Prevalence of blindness and MSVI increases dramatically after the age of 50. Considering the rapid aging of the population in the region, the burden of cataract and age-related glaucoma caused vision impairment is expected to increased dramatically and constitutes a major challenge for eye care services in this region. Increased effort should be made for the screening of eye diseases among the elderly. Especially, advocacy by international academic organizations such as WHO and IAPB towards governments should be strengthened with regard to the integration of eye care into primary health care.
As for the change in causal contribution to age-standardized prevalence of blindness in adults 50+ years from 1990 to 2020, contribution by diabetic retinopathy increased by 45.3%, which is a clear signal regarding the importance of incorporating the eye care in to chronic disease management.
RC: Policy makers in these regions should be mindful that:
- Visual impairment remains a serious public health issue.
- Most visual impairment is correctable.
- As certain areas become more prosperous, the international community will expect that some of that prosperity is directed towards eliminating avoidable visual impairment.
What are the 3 key take away messages you would like to the eye health sector to know about vision loss in your region?
NW: The age-standardized prevalence of blindness and mild vision impairment dropped in all three regions from 1990 to 2020. However, while the age-standardized prevalence of moderate/severe vision impairment decreased in Southeast Asia and Oceania, the prevalence increased in East Asia, revealing the great challenges brought by the increase in myopia and also chronic disease related eye disease such as diabetic retinopathy. The research on these emerging diseases, such as the high myopia, should be carried out.
There was a 286.7% percentage change in cases of blindness caused by diabetic retinopathy from1990 to 2020. One key way to strengthening the early screening, detection and treatment of diabetic retinopathy would be the application of artificial intelligence, mobile-health, and tele-ophthalmology, etc. The research, especially, large population-based programs, verifying the effectiveness of such new strategies should be in place so as to better deal with the new developments and challenges.
There isn’t enough ophthalmic epidemiological data from developing regions, while 90% of people with preventable visual impairment are in fact living in low-and middle-income countries. The ophthalmic epidemiological data are crucial for the development of proper plans and strategies, thus national or subnational surveys should be carried out on a regular basis.
Diabetic eye disease is an emerging serious public health problem.
Age-related eye diseases like macular degeneration are becoming increasingly common as life expectancies improve.
The problem of visual impairment is tractable.
In your region, how have the patterns of vision loss changed over time? Are you able to present any theories about why these changes have occurred?
NW: The age-standardized prevalence of moderate and severe visual impairment attributable to cataract increased by 15.9%, while its contribution to the age-standardized prevalence of blindness dropped by 40.9%. With the increase of cataract surgical rate and the popularization of cataract surgery technology, the blindness caused by cataract is decreasing, however, the quality of the surgery should be the focus for the next step. WHO has introduced a new indicator for the monitoring of the surgery quality, effective cataract surgery coverage (eCSC). The moderate and severe visual impairment caused by glaucoma and age-related macular degeneration increased and the age-standardized prevalence of blindness also decreased, which could be explained by strengthened screening and improvement in surgical techniques and related interventions. More importantly, the issue of diabetic retinopathy is definitely drawing more attention, and screening and early intervention is crucial.
RC: We are seeing more degenerative eye diseases as populations live longer and also more diabetic eye disease as diets change. The increase in myopia remains a serious public health issue in some Asian regions and may be related to an increase in near visual tasks during childhood.
Does the data tell you anything about how services have been responding to need?
NW: This data can clearly reflect the urgent need of coping with the challenges brought by eye diseases related to chronic systematic diseases. Along the epidemiological stages, the chronic non-communicable disease will definitely become the main issue. In addition, the challenges brought by the refractive error should draw our attention, especially for conditions that could be addressed by a pair of glasses should not be the reason that people’s life quality is compromised. It is crucial that we continue our efforts in ending avoidable blindness.
RC: The data doesn’t really track the response of services to need, but we do know that the response is not meeting the increased burden due to the ageing population.
What surprised you about the data?
NW: It is expected the diabetic retinopathy has becoming a major issue. However, to see its contribution to age-standardized prevalence of blindness increase by over 45% is still quite shocking. The challenge brought by diabetic retinopathy was also shocking in China. Though as a developing country, China has made great progress in the prevention of blindness and was able to reduce the age-standardised prevalence of blindness by 24·53%, and among the diseases leading to blindness, only the age-specific prevalence of diabetic retinopathy had a positive effect on the increase in the number of people with blindness, and this factor contributed more to the increase in the number of people with blindness than ageing population.
RC: The relative paucity of epidemiological data from these regions.
Have any ‘good news’ stories emerged from the data in your region?
NW: The age-standardized prevalence of both mild vision impairment and blindness dropped in all three regions, which indicates the progress made in the prevention and treatment of vision-compromising eye diseases. And for the moderate to severe vision impairment, its age-standardized prevalence dropped in both Southeast Asia and Oceania. However, due to the burden of refractive error in the East Asia, the prevalence in East Asia increased by 9.1%.
RC: The population in these regions has generally seen an increase in prosperity and health over recent decades and life expectancies are increasing.
What concerns you most about vision loss trends in your region?
NW: The changes in lifestyle and the aging population will lead to increased need for the eye care services. Merely relying on the training of personnel will not be able to cope with the need, thus the progress on the research and application of AI, mobile health and teleophthalmology are in urgent need.
RC: The increase in diabetic eye disease is a serious concern and seems likely to increase with time.
Are there any additional data elements (causes, populations) that you would like to see included in future studies?
NW: As explained above, the quality, accessibility and affordability of eye care services would be the indicators, and thus relevant data, the coverage and effective coverage of services, should be great value.
Image on top: Post cataract with their doctors outside a bus/ 廉行文
RC: A better understanding of the trends in causes of childhood blindness would be important information.