The Myopia Epidemic: Beyond Near-Sightedness
Myopia, colloquially known as near-sightedness, extends beyond being a political metaphor for lacking foresight, increasingly becoming a global challenge. In 2010, myopia was reported to affect 1.45 billion people globally, or 27% of the human population. This number is only set to rise: by 2050, rates of myopia are predicted to reach 50% (Holden et al. 2016). And whilst myopia, which is commonly corrected in the developed world with glasses or contact lenses, doesn’t initially seem to be a grand challenge worth tackling, the issue transcends mere vision impairment. It is associated with a plethora of more sinister complications such as macular degeneration, cataracts, and retinal detachment that healthcare systems must strive to avoid (Haarman et al. 2020).
Defined simply as a refractive error where distance vision becomes blurry but near vision remains in focus, myopia occurs due to elongation of the eyeball. This phenomenon misdirects light before it reaches the retina, impacting detailed sight (Figure 1). Myopia is a complex trait with causal factors categorised as either genetic or environmental, and both playing a significant role. Some of the more concerning lifestyle factors driving the increase in prevalence of the condition include spending too much time in front of near work; insufficient time spent outdoors; and low levels of light exposure (Holden et al. 2015). And these risk factors are already having a clear impact in some populations more than others, notably young people in East Asia with one study citing a 96.5% prevalence in Koreans aged nineteen years old (Pan et al. 2015). However, corrective action through good public health policy and education offers hope in mitigating these risks.
Figure 1 - https://www.honolulueyeclinic.com/what-is-myopia/
Myopia is a progressive condition, meaning that a person’s eyesight will deteriorate over the span of months and years. But it is entirely manageable with refractive techniques such as contact lenses and glasses. Additionally, the cost of these is not an issue in the countries with the highest burden, as these tend to be more affluent, industrialised countries with a higher socioeconomic status and associated causative lifestyle (Foster and Jiang 2014). The challenge lies in how to prevent the progression of myopia, to reduce the likelihood of developing complications. Currently there are 2 leading strategies: orthokeratology and atropine eye drops. The former refers to using a specially shaped contact lens that temporarily re-shapes the eye so that it refracts correctly again, similar to orthodontics for teeth (‘What Is Orthokeratology?’ 2023); and the latter an evolving approach only recently verified in landmark trials in East Asia and uses a medicine commonly used to treat a slow heartbeat, to prevent deterioration and even onset of myopia (Chia et al. 2012). Current understanding shows that the most important factor in prevention of the condition is increasing time away from near work and better light intensity in indoor living spaces.
For a long time, myopia has flown under the radar considered as a benign refractive error, but its emergence as an epidemic demands attention. Beyond eye specialists, its impact on global productivity is substantial, being estimated at $202 billion in the US alone (Holden et al. 2015). A collaborative effort to tackle the rise of myopia and its insidious pathologic side, which at the moment is not included in financial burden estimates, will be needed for the world to not suffer great consequences from the myopia epidemic. It is vital that the future generations of opticians and clinicians be informed on active myopia control, and it be embraced as a core element of healthcare systems going forward (McCrann, Flitcroft, and Loughman 2020).
Sources:
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Foster, P J, and Y Jiang. 2014. ‘Epidemiology of Myopia’. Eye 28 (2): 202–8. https://doi.org/10.1038/eye.2013.280.
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Pan, Chen-Wei, Mohamed Dirani, Ching-Yu Cheng, Tien-Yin Wong, and Seang-Mei Saw. 2015. ‘The Age-Specific Prevalence of Myopia in Asia: A Meta-Analysis’. Optometry and Vision Science: Official Publication of the American Academy of Optometry 92 (3): 258–66. https://doi.org/10.1097/OPX.0000000000000516.
‘What Is Orthokeratology?’ 2023. American Academy of Ophthalmology. 23 April 2023. https://www.aao.org/eye-health/glasses-contacts/what-is-orthokeratology.