The Unseen Epidemic: Myopia

Writter By: Faizan Khan

Post By: Gauri

The world is seeing increasing rates of myopia, the near-sightedness of the eyes, with data predicting that 50% of the world’s population could be affected by this condition by 2050.^1,2,3 The world has also seen an exponential rise in the prevalence of digital technology over the past few decades. Well, the answer seems obvious: It’s all because of those darn phones! At least, that might be what parental-wisdom states. Yet, science tells us correlation does not always equal causation, and the truth lies in the details.

Before understanding myopia, let’s first understand how our eyes work. Light initially passes through the clear front layer of the eye, called the cornea, which bends the light to help the eye focus.⁴ Some of the light enters the pupil, with the amount of light being let in controlled by the iris.⁴ Then, the light is focused on the retina at the back of the eye through the inner lens, with the help of the cornea.⁴ The retina is the key to enabling sight, as it is a light-sensitive layer of tissue consisting of specialized cells called photoreceptors: these cells convert the light into electrical signals that travel through the optic nerve to the brain, and thus are translated into the image that we see.⁴ 

The components of an eyeball.⁴

The common form of myopia occurs when the eyeball lengthens to accommodate near-sighted vision, resulting in light being focused in front of the retina rather than directly on it.^5,6,7 This makes distant images appear blurry, but closer objects are clear.  Other causes include progressive thinning of the cornea and nuclear cataracts in adults 50 years and older, but these instances are rarer and have different risk factors associated with them.⁶

Elongation of the eyeball due to myopia causes light being focused in front of the retina.⁵

The most prevalent cause of myopia is genetics.⁶ If one of your parents has myopia, then you are as likely to inherit it as well. Otherwise, there is strong evidence to suggest that the environment has a significant impact on vision.^6,7 Development of the eye is characterized by constant adjustments to its shape in response to different visual stimuli.⁷ If a task is being performed that requires focusing on a short-distance object, the eye will elongate itself.⁷ If the eye becomes too long, ‘stop signals’ help ensure the eye can return to normal.⁷

Although experts are unsure of the exact source of these stop signals and what may cause a lack of them, research using animal models suggests that the release of dopamine in response to high levels of ambient sunlight is a likely starting point.⁷

Generally, more time spent outdoors has been correlated with fewer chances of myopia developing.^7,8 Studies on a large sample of Australian schoolchildren, Chinese schoolchildren, and animals, including monkeys and chicks, all show the inhibitory effect of a sunlit, outdoor environment on the progression of myopia when compared to individuals primarily in an indoor environment.^8,9,10

Another theory proposes an alternate origin for the stop signal: rather than sunlight being the trigger, it is instead the different visual “blur” that can be seen in an outdoor environment.⁷ Picture what you may typically see outside: a diverse array of textures viewed at considerable distances, such that details are displayed as a more cohesive, picturesque image from afar. Our eyes are essentially trained to view these faraway images.⁷ This is in contrast to the various objects of all shapes, sizes, and distances we have in interior environments, surrounded by flat, blank walls. Our eyes constantly adjust their focus in this environment, and so the retina lacks the stop signal preventing excessive eye growth.⁷

Regardless of whether it is sunlight or the landscape outside, research shows that the way to mitigate the myopia crisis is simple: spend more time outdoors.⁷ Myopia rates have already been reduced up to 50% in schoolchildren given 50 to 80 extra minutes outside, according to studies in Taiwan and China.² However, our modern lifestyle doesn’t always make it that simple.

Although phones and other devices may not be a cause for concern, it is the habits we develop as a result of using them that perpetuate the issue. Consider where someone might spend most of their time in front of a screen: whether it be doomscrolling in bed, sitting in front of a computer in an office, or playing video games on the living room TV, one is most likely to be indoors while participating in an activity involving a screen. Of course, this doesn’t just apply to our devices. Spending large amounts of time reading, doing homework, or any other activity indoors without extra outdoor time can cause the onset of the problem.¹¹

Due to the potential long-term symptoms of severe myopia not being apparent in someone until years later, many often don’t realize the full brunt of the problem.^2,11 It’s not just having glasses that a person may have to be worried about; up to 15% of patients with severe myopia are at risk for disorders including glaucoma, retinal detachment, cataract, or even blindness.² It is for these reasons that focusing on this epidemic and controlling it has become vital to scientists and healthcare professionals around the world.

Many methods have been developed to counter progressive myopia. More open classrooms with lots of windows allow for access to sunlight.⁷ Some classrooms in China have painted walls depicting outside scenery to stimulate the eye, similar to a natural environment.⁷ Other methods aim to treat myopia after onset using different wavelengths of light.⁷ Nevertheless, the easiest answer also happens to be the cheapest: step outside, take a deep breath, and take a look at the world around you!

References

1. Holden BA, Mariotti SP, Kocur I, Resnikoff S, He M. The impact of myopia and high myopia: report of the Joint World Health Organization – Brien Holden Vision Institute Global Scientific Meeting on Myopia. University of New South Wales, Sydney, Australia. World Health Organization. 2015 Mar. https://myopiainstitute.org/wp-content/uploads/2020/10/Myopia_report_020517.pdf

2. Stuart, A. Facing the myopia epidemic. American Academy of Ophthalmology. 2020. https://www.aao.org/eyenet/article/facing-the-myopia-epidemic

3. Brien A. Holden, Timothy R. Fricke, David A. Wilson, Monica Jong, Kovin S. Naidoo, Padmaja Sankaridurg, Tien Y. Wong, Thomas J. Naduvilath, Serge Resnikoff. American Academy of Ophthalmology. Global Prevalence of Myopia and High Myopia and Temporal Trends from 2000 through 2050. Ophthalmology. 2016 May;123(5):1036–42.  10.1016/j.ophtha.2016.01.006 External Link

4. National Eye Institute. How the Eyes Work | National Eye Institute. https://www.nei.nih.gov/learn-about-eye-health/healthy-vision/how-eyes-work

5. Hobbs H. Nearsightedness (Myopia). Healthline. 2022. https://www.healthline.com/health/nearsightedness#causes

6. Myopia (Nearsightedness). Cleveland Clinic. 2025. https://my.clevelandclinic.org/health/diseases/8579-myopia-nearsightedness

7. Dolgin E. A myopia epidemic is sweeping the globe. Here’s how to stop it. Nature. 2024 May 29;629(8014):989–91. doi: https://doi.org/10.1038/d41586-024-01518-2

8. Read SA, Collins MJ, Vincent SJ. Light exposure and eye growth in childhood. Investigative Ophthalmology & Visual Science. 2015 Oct 21;56(11):6779. 10.1167/iovs.14-15978

9. He M, Xiang F, Zeng Y, Mai J, Chen Q, Zhang J, et al. Effect of time spent outdoors at school on the development of myopia among children in China. JAMA. 2015 Sep 15;314(11):1142. 10.1001/jama.2015.10803

10. Carr BJ, Stell WK. The science behind myopia. National Library of Medicine. 2017. https://www.ncbi.nlm.nih.gov/books/NBK470669/

11. Baird PN, Saw SM, Lanca C, Guggenheim JA, Smith EL III, Zhou X, et al. Myopia. Nature Reviews Disease Primers. 2020 Dec 17;6(1):99. https://doi.org/10.1038/s41572-020-00231-4