What Causes Myopia?

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Written by Optometrist Megan Lafferty, contact us to book an appointment with Megan.

Singapore has been called the “Myopia Capital of the World” as the rates here are among the highest recorded worldwide and are increasing dramatically1. Statistics show 65% of our children being myopic by as young as P6 and 83% by young adulthood2 meaning myopia is reaching “epidemic” level proportions in our country.
Myopia causes blurred vision due to an improper focussing of light caused by either the structures of the eye being too curved or the eyeball itself growing too long, but why does this happen?
Let’s look at the various factors contributing to the development and progression of myopia:

Genetics3

One of the primary causes of myopia is genetic predisposition. Individuals with a family history of myopia are at a higher risk of developing the condition themselves and researchers have identified several genes associated with myopia which can influence the growth and shape of the eyeball. Children with both myopic parents are at higher risk than those with one and as rates are already so high in Singapore.

Ethnicity4

As well as family inherited genetics, ethnicity plays a role in likelihood of myopia development and progression. It has been shown that children of Asian descent (particularly East/Southeast Asian) show faster myopia progression than white patients meaning Asians are much more susceptible to developing myopia and progressing to higher degrees.

Excessive Near Work5

Engaging in prolonged periods of near work, such as reading, using electronic devices, or studying, has been linked to myopia development.The increased demand on the eye’s focusing mechanism during these activities may contribute to growth of the eyeball, leading to myopia.

Lack of Outdoor Activities5

Insufficient time spent outdoors, especially during childhood, has been associated with a higher risk of myopia. Outdoor activities seem to have a protective effect, presumably due to exposure to natural light or the relaxation of the eye’s focusing muscles; however the exact relation is still unknown.

Age and Development6

Myopia often begins in childhood and tends to progress during the school-age years as the child grows and their eyeball length increases. It has been shown that the earlier the onset of myopia, the higher the likelihood of progression i.e. the younger a child develops myopia, the more likely they are to progress to higher degrees which can be detrimental to their eye health and vision.
With the modern day urban lifestyle in Singapore which puts heavy importance on childhood academia and a culture that tends towards less outdoor time and more screen time (especially since the pandemic<sup>7</sup>), it is no wonder that there is a rising prevalence of myopia here. Although there is not a lot that can be done about genetic factors of myopia development, understanding the environmental influences and adopting “Myopia Control” methods can help us manage and hopefully prevent future generations of Singaporeans from suffering the effects of myopia!
To find out about myopia control methods please click here.

References:

  1. B. A. Holden, T. R. Fricke, D. A. Wilson, M. Jong, K. S. Naidoo, P. Sankaridurg, T. Y. Wong, T. J. Naduvilath, S. Resnikoff. Global Prevalence of Myopia and High Myopia and Temporal Trends from 2000 through 2050. Epub (2016) doi:10.1016/j.ophtha.2016.01.006 (https://pubmed.ncbi.nlm.nih.gov/26875007/)
  2. I. Ng, W.T. Yin. Speech by Dr Lam Pin Min, Senior Minister of State for Eye Health at the Opening of Singapore National Eye Centre’s Myopia Centre. Ministry of Health Singapore (2019) (https://www.moh.gov.sg/news-highlights/details/speech-by-dr-lam-pin-min-senior-minister-of-state-for-health-at-the-opening-of-the-singapore-national-eye-centre-s-myopia-centre-16-august-2019/)
  3. X. Zhang, X. Qu, and X. Zhou. Association between parental myopia and the risk of myopia in a child. Exp Ther Med (2015) doi:10.3982/etm.2015.2415 (https://ncbi.nlm.nih.gov/pmc/articles/PMC4473431/)
  4. T. Q. Luong, Y. H. Shu, B. S. Modjtahedi, D.S. Fong, N.Choudry, Y. Tanaka,and C. L. Nau. Racial and Ethnic Differences in Myopia Progression in a Large Diverse Cohort of Paediatric Patients. IOVS (2020) doi:10.1167/iovs.61.13.20 (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7671858/)
  5. J. Cooper & A. V. Tkatchenko. A Review of Current Concepts of the Etiology and Treatment of Myopia. Eye Contact Lens (2018) doi:10.1097/ICL.0000000000000499 (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6023584/)
  6. P. K. Verkicharla, P. Kammari, A. V. Das, J F Hejtmancik. Myopia progression varies with age and severity of myopia. PLoS One (2020) doi:10.1371/journal.pone.0241759 (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7678965/)
  7. C. W. Wong, A.Tsai, J. B. Jonas, K. Ohno-Matsui, J. Chen, M. Ang and D. S. Tinga. Digital Screen Time During the COVID-19 Pandemic: Risks for a Further Myopia Boom? Am J Ophthalmol (2021) doi:10.1016/j.ajo.2020.07.034 (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7390728/)