Gabriel Kwaku Agbeshie,
Guest contributor
10 November 2026
Short-sightedness (myopia) is caused by the eye becoming too elongated to see objects at distance clearly. It is becoming much more common, and by 2050 about half of the world’s population may be myopic [1]. The more myopic a person is, the more risks he or she faces during his or her lifetime of serious eye diseases like retinal detachment, glaucoma and myopic macular degeneration [2], and it is not an inconvenience that common eyeglasses can remedy. Yet most of what we know about how children’s daily light and visual habits shape myopia comes from a few parts of the world. Africa, where daylight is plentiful and childhood myopia is rising, is almost absent. This article is about that gap and the importance of research in this area.
The two big questions
What keeps a child from becoming short-sighted in the first place (onset), and once myopic, what slows it from getting worse (progression)? A 2024 Cochrane review found that school programmes that add outdoor time may reduce the number of children who develop myopia, but the effect on how quickly existing myopia worsens remains uncertain [3].
To understand how the evidence fits together, I selected studies of three aspects of children’s visual experience (light exposure, viewing distance, and colour of light) and organised them as comparisons on the Open Research Knowledge Graph (ORKG). The ORKG is an open platform that turns findings trapped in papers into side-by-side structured tables. I conducted a PubMed, Google Scholar, and Scopus search, screened the titles, abstracts and full texts, and noted the design of each study, the population studied, the method used to measure exposure, and the visual outcomes of the study.
So far, eleven studies were included: six on light illuminance, two on viewing distance and three on light colour. All the studies can be compared side by side and added to by anyone, making it a “living document.”
Myopia onset and progression were highlighted in comparisons between these studies. In Shanghai, outdoor light exposure of at least 15 minutes and more than 2,000 lux in almost 3,000 children without myopia was associated with a decreased shift towards myopia [4]. This is not to say that 15 minutes a day is sufficient to protect against myopia. Conversely, another study in the US with 835 myopic children did not show an association between outdoor activities and the progression of myopia [5].
In Taipei, already myopic children whose parents reported a reading distance of more than 30 cm worsened less than those who read closer [6]. This is a distance within a single population and is not a safe near-work distance for everyone. The three colour studies were short laboratory experiments, mostly in young adults, that measured tiny, temporary changes in eye length rather than myopia, and their results differed [7-9]. It remains to be seen just how applicable they are in everyday lighting.
The African gap
There were no studies from Africa in this comparison of eleven studies. This reflects the wider literature. The largest African review pooled data from 42 surveys across 19 of the continent’s 54 countries and found that childhood myopia had roughly doubled since 2010 [10]. Such surveys are snapshots of cases at a point in time. No African study has quantified how much light children are exposed to using a wearable sensor and tracked how their eyes have grown over time. So, we cannot tell whether findings from the Western part apply to Africa. As a matter of global equity, recommendations for protecting children’s eyes should rest on evidence from the children they aim to protect.
What should come next?
In Denmark, myopic children’s eyes grew more slowly during long summer days than during short winter days [11], but day length, brightness and school routines all change together with the seasons. Near the equator, days last about 12 hours all year and outdoor light is intense, so following Ghanaian children could help show whether brightness, rather than day length, protects the eye. The priority is long-term studies that measure, in the same children, light exposure, near-work distance, and myopia. At the Technical University of Munich, I am developing a pilot study that follows schoolchildren for a year, using the Visual Environment Evaluation Tool (VEET) alongside ocular measurements. Taking this approach to Africa would help us compare children and also help contribute to the question that the current evidence leaves open: is it the amount of light a child’s eyes receive, the way they use their eyes up close, or both that determine whether myopia starts and how fast it grows?
References:
1. Holden, B.A., et al., Global Prevalence of Myopia and High Myopia and Temporal Trends from 2000 through 2050. Ophthalmology, 2016. 123(5): p. 1036-1042. DOI: https://doi.org/10.1016/j.ophtha.2016.01.006.
2. Haarman, A.E.G., et al., The Complications of Myopia: A Review and Meta-Analysis. Investigative Ophthalmology & Visual Science, 2020. 61(4): p. 49-49. DOI: https://doi.org/10.1167/iovs.61.4.49.
3. Kido, A., M. Miyake, and N. Watanabe, Interventions to increase time spent outdoors for preventing incidence and progression of myopia in children. Cochrane Database of Systematic Reviews, 2024(6). DOI: https://doi.org/10.1002/14651858.CD013549.pub2.
4. Chen, J., et al., Smartwatch Measures of Outdoor Exposure and Myopia in Children. JAMA Network Open, 2024. 7(8): p. e2424595-e2424595. DOI: https://doi.org/10.1001/jamanetworkopen.2024.24595.
5. Jones-Jordan, L.A., et al., Time Outdoors, Visual Activity, and Myopia Progression in Juvenile-Onset Myopes. Investigative Ophthalmology & Visual Science, 2012. 53(11): p. 7169-7175. DOI: https://doi.org/10.1167/iovs.11-8336.
6. Huang, P.-C., et al., Protective behaviours of near work and time outdoors in myopia prevalence and progression in myopic children: a 2-year prospective population study. British Journal of Ophthalmology, 2020. 104(7): p. 956. DOI: https://doi.org/10.1136/bjophthalmol-2019-314101.
7. Chakraborty, R., et al., Axial length reduction and choroidal thickening with short-term exposure to cyan light in human subjects. Ophthalmic and Physiological Optics, 2024. 44(7): p. 1414-1432. DOI: https://doi.org/https://doi.org/10.1111/opo.13390.
8. Clement, S.P., et al., Influence of Aberration-Free, Narrowband Light on the Choroidal Thickness and Eye Length. Translational Vision Science & Technology, 2024. 13(4): p. 30-30. DOI: https://doi.org/10.1167/tvst.13.4.30.
9. Swiatczak, B. and F. Schaeffel, Myopia: why the retina stops inhibiting eye growth. Scientific Reports, 2022. 12(1): p. 21704. DOI: https://doi.org/10.1038/s41598-022-26323-7.
10. Kobia-Acquah, E., et al., Regional variations and temporal trends of childhood myopia prevalence in Africa: A systematic review and meta-analysis. Ophthalmic and Physiological Optics, 2022. 42(6): p. 1232-1252. DOI: https://doi.org/https://doi.org/10.1111/opo.13035.
11. Cui, D., K. Trier, and S. Munk Ribel-Madsen, Effect of Day Length on Eye Growth, Myopia Progression, and Change of Corneal Power in Myopic Children. Ophthalmology, 2013. 120(5): p. 1074-1079. DOI: https://doi.org/10.1016/j.ophtha.2012.10.022.
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