Why Are More Children Becoming Nearsighted?

This student blog post is written by Elios S. and is about myopia, also known as being nearsighted, and the incidence of this eye condition in children. Want to learn more? Take it away, Elios!

“It’s those phones you always have in your hand!”

This is a phrase we’ve all heard many times when we mention not seeing the board at school… (Or just any problem!) But even though this comment is often used jokingly, it reflects real concern. More children seem to be wearing glasses nowadays than in the past, this raises an important question: why is this happening? There is a growing number of children who have developed myopia, also known as nearsightedness. This is a condition which makes objects that are far away appear blurry. Myopia happens when the eye grows in a way which causes the light to focus right in front of the retina instead of being right on it (see Figure 1). The rise of nearsightedness seems to be due to modern habits, especially less time outdoors and close-up visual work.

Figure 1. Exaggerated representation of normal vision and myopia caused by abnormal eye growth. In myopia, light focuses in front of the retina instead of directly on it. Image from Carr & Stell (2017).

When the myopia develops, one of the most obvious changes is that the eye grows too long from front to back, this means that light reaches its focus point before it even gets to the retina (Morgan et al., 2012; French et al., 2013). The change in length is rather small, but it has a major effect on a person’s vision because the retina is no longer able to receive a sharp image from further away (Morgan et al., 2012). This is a clear reason why myopia is treated differently from just bad eyesight. It is a biological change in how the eye develops over time (Morgan et al., 2018). Children need glasses, because their eyes mature past the preferred point; they grow in a way which makes distant objects more difficult to focus on.

Myopia, or nearsightedness, happens when the light which enters the eye does not focus on the light in the correct position (Morgan et al., 2012). For normal vision, light enters the eye and is bent by the cornea and the lens so that it lands directly on the retina; the retina is light-sensitive tissue at the back of the eye (Morgan et al., 2012). When this process works properly, the brain receives a clear image. But in a nearsighted eye, the light focuses right in front of the retina instead. This makes far-away objects seem blurry, but the nearby objects remain clear (Morgan et al., 2012; Morgan et al., 2018). Myopia is a problem of the eye’s shape and the focus, a small change in how the eye grows can greatly affect how clearly a child will see the world (Morgan et al., 2018; French et al., 2013).

Myopia is also linked to several changes in many important parts of the eye. The retina, which is light-sensitive tissue at the back of the eye, detects the light and may also help to signal whether the eye is focusing properly. Right behind it is the retinal pigment epithelium (RPE), which is a layer of support cells which aid to nourish the retina; they also remove waste and pass signals through the eye (see figure 2). And behind the RPE there is a blood rich layer that helps supply oxygen and nutrients to the outer layer of the eye, which is named the choroid. The choroid also takes part in growth-related signaling. The sclera, which is the white tough outer layer of the eye, is a part of the eye which gets stretched out when the myopia is developed (Zhang & Wildsoet, 2015; Harper & Summers, 2015).

Figure 2. Labeled diagram of the human eye showing major structures involved in vision, including the cornea, lens, retina, sclera, and optic nerve. Reprinted from the National Eye Institute (2025).

It is believed that the recent rise in childhood myopia is linked to the changes in how children live their lives and use their eyes (Morgan et al., 2018). In the present-day children now spend more time doing close visual work, which is also referred to as near work. This includes reading, doing homework, and using their phones/iPads/laptops for long periods of time. (Dutheil et al., 2023; Ha et al., 2025). This is also the main reason for many kids’ spending way less time outdoors compared to the past, this matters because children who spend more time outdoors are less likely to become nearsighted (French et al., 2013; Xiong et al., 2017; He et al., 2022). There is still research going on about why exactly outdoor light helps the eye grow in a healthy manner during the growth of a child (French et al., 2013; He et al., 2022). Once myopia is developed, glasses are used to fix it by bending light so that it lands more accurately on the retina. This makes distant objects look clearer again (Morgan et al., 2012). But glasses do not fix the eye; they just correct the way light enters the eye (Morgan et al., 2012; Morgan et al., 2018).

Children are needing glasses because myopia is becoming increasingly common; myopia is developed when the eye grows too long from front to back which causes the light to focus on the front of the retina instead of directly on it. This makes childhood myopia a clear example of how the structure of the eye affects its function. Research suggests that the rise in myopia is linked to modern habits of spending more time inside doing near work, outdoor time is shown to be very important for children’s eyes especially. There is still research going on why outdoor time is beneficial for healthy eye growth. Overall, childhood myopia shows how everyday habits can influence the way the body develops, and why a common problem like needing glasses is also an important topic in biology.

Works Cited:

Carr, B.J., & Stell, W. K. (2017). The Science Behind Myopia. Webvision: The Organization of the Retina and Visual System [Internet]. Available: https://www.ncbi.nlm.nih.gov/books/NBK470669/

Dutheil, F., Oueslati, T., Delamarre, L., Castanon, J., Maurin, C., Chiambaretta, F., Baker, J. S., Ugbolue, U. C., Zak, M., Lakbar, I., Pereira, B., & Navel, V. (2023). Myopia and near work: A systematic review and meta-analysis. International Journal of Environmental Research and Public Health, 20(1), 875. https://doi.org/10.3390/ijerph20010875

French, A. N., Ashby, R. S., Morgan, I. G., & Rose, K. A. (2013). Time outdoors and the prevention of myopia. Experimental Eye Research, 114, 58–68. https://doi.org/10.1016/j.exer.2013.04.018

Ha, A., Lee, Y. J., Lee, M., Shim, S. R., & Kim, Y. K. (2025). Digital screen time and myopia: A systematic review and dose-response meta-analysis. JAMA Network Open, 8(2), e2460026. https://doi.org/10.1001/jamanetworkopen.2024.60026

Harper, A. R., & Summers, J. A. (2015). The dynamic sclera: Extracellular matrix remodeling in normal ocular growth and myopia development. Experimental Eye Research, 133, 100–111. https://doi.org/10.1016/j.exer.2014.07.015

He, X., Sankaridurg, P., Wang, J., Chen, J., Naduvilath, T., He, M., Zhu, Z., Li, W., Morgan, I. G., Xiong, S., Zhu, J., Zou, H., Rose, K. A., Zhang, B., Weng, R., Resnikoff, S., & Xu, X. (2022). Time outdoors in reducing myopia: A school-based cluster randomized trial with objective monitoring of outdoor time and light intensity. Ophthalmology, 129(11), 1245–1254. https://doi.org/10.1016/j.ophtha.2022.06.024

Morgan, I. G., French, A. N., Ashby, R. S., Guo, X., Ding, X., He, M., & Rose, K. A. (2018). The epidemics of myopia: Aetiology and prevention. Progress in Retinal and Eye Research, 62, 134–149. https://doi.org/10.1016/j.preteyeres.2017.09.004

Morgan, I. G., Ohno-Matsui, K., & Saw, S.-M. (2012). Myopia. The Lancet, 379(9827), 1739– 1748. https://doi.org/10.1016/S0140-6736(12)60272-4

National Eye Institute. (2025). About the eye. NEI for Kids. Available: https://www.nei.nih.gov/eye-health-information/healthy-vision/nei-for-kids/about-eye

Xiong, S., Sankaridurg, P., Naduvilath, T., Zang, J., Zou, H., Zhu, J., Lv, M., He, X., & Xu, X. (2017). Time spent in outdoor activities in relation to myopia prevention and control: A meta-analysis and systematic review. Acta Ophthalmologica, 95(6), 551–566. https://doi.org/10.1111/aos.13403

Zhang, Y., & Wildsoet, C. F. (2015). RPE and choroid mechanisms underlying ocular growth and myopia. Progress in Molecular Biology and Translational Science, 134, 221–240. https://doi.org/10.1016/bs.pmbts.2015.06.014