Preventing High Myopia
- Posted on: Sep 10 2019
By Dr. Luis Washington Lu, M.D. based on the article by Jennifer Sha
By 2020 the global prevalence of myopia and high myopia are estimated to be 34% and 5.4% respectively and are predicted to increase. Due to the increased risk of developing complications such as retinal detachment, glaucoma, cataract, and myopic macular degeneration, much effort has been made in recent decades to understand myopia progression and methods of slowing its progression.
Stabilization of the eye vision (Emmetropization) is the process that occurs during childhood and adolescence whereby the axial length of the eye is regulated to closely match the refractive power. Most infants are farsighted, and while Emmetropization reduces the refractive error, children typically reach to a low level of farsightedness by teen years.
However, Emmetropization does not always proceed in this manner, and in children that become myopic, axial length is longer and refractive error is less hyperopic (farsighted) than normal for up to three years before even the onset of myopia.
Research has uncovered some characteristics of people at greater risk of developing myopia. These include at least one parent with myopia, female gender, very close reading distances and longer continuous reading time.
Age is an interesting factor, as the prevalence of myopia is higher in older children, while the progression rate is greater in younger children. In terms of ethnicity, myopia prevalence is significantly higher in east Asian children compared to Caucasian children even in the same geographic location. Moreover, myopia progression is higher in Asian children compared to Caucasian children. It is not completely clear if these ethnicity differences are due to genetic factors, environmental factors, or both as East Asian children also spend less time outdoors on average than their Caucasian counterparts, which is also a risk factor for developing myopia.
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