Myopia most commonly originates from the elongation of the eyeball. Excessive elongation of the eyeball increases the risks of permanent vision loss due to cataract, glaucoma and macular changes.
Traditional means of vision correction like glasses, contact lenses and refractive surgery, relieve the symptoms of blurry vision by only helping you to see better. However, these options do not slow or halt the excessive elongation of the eyeball.
There are now options available to slow down/halt the abnormal eyeball elongation thereby slowing down the progression of myopia. By reducing the abnormal elongation, the risks of possible vision loss can be reduced.
In saying that, monitoring your child's myopia progression should rightfully be done with axial length (eyeball length) instead of just the glasses prescription.
Babies are born with an eyeball length of approximately 16-17mm. The average length of a mature eye (12-15 years of age) is 23.8mm. The growth of an eyeball beyond the normal length results in myopia. The elongation not only cause blurry vision, it also results in the increased risk of vision impairment when older.
A 2016 study showed that, 39% of people with with high myopia (larger than -6.00D) developed visual impairment by the age of 75. The following table shows the risk of developing visual impairment in relationship to eyeball length.
Myopia is a multifactorial disease and the exact cause is still unknown. The risk factors of Myopia are the following:
Having parents with myopia increases the chances of a child developing myopia. Studies have found that identical twins are more likely to have similar prescriptions and eye length than non-identical twins. The heritability of eyeball length is also high, at over 90%. East Asian children have a higher incidence of myopia compared to European Caucasian children, which suggests that there may be a genetic component to the development of myopia.
Children who spend less time outdoors and have less exposure to natural lighting are more likely to develop myopia. Research has found that outdoor activity reduces the prevalence of myopia in children. Studies have also found that high population density and smaller homes are associated with increased eyeball elongation and childhood myopia, which suggests that the environment in which a child grows up may also play a role in the development of myopia.
Prolonged near tasks such as reading and using electronic devices at close distances have become more prevalent in today's digital age, which has led to an increase in the incidence of myopia. A study found that the COVID-19 pandemic and the resultant increased screen time have led to an increased prevalence of myopia in children. Another study also found that increased screen time and decreased outdoor time during the pandemic were associated with an increased risk of myopia in children.
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