There are two major hazards to the eyes when smartphones are used for prolonged periods ("Are smartphones hurting our eyes?" by Ms Lim Lih Mei; Monday).
First, it can contribute to an increase in myopia among young children, especially those with a family history of the condition. The risk is similar to that when reading a book.
In young adults whose myopia has stabilised, prolonged near work can cause visual strain - the symptoms are headache, general eye discomfort and blurred vision.
Second, most smartphones use light-emitting diode (LED) screens, which emit a lot of blue light. Blue light has a shorter wavelength and greater energy, and can induce photochemical damage to the retina of the eye. This is a slow process where damage accumulates over a lifetime, and may play a role in the pathogenesis of retinal degenerative diseases such as age-related macular degeneration.
Young children should take visual breaks when performing prolonged near work. They could go outdoors more often to slow down or prevent myopia progression, and wear sunglasses or UV-protected clear optical lenses when the sun is bright. There are also optical lenses that can protect the eyes from the harmful blue light emitted by LED screens.
It is advisable for those who spend a lot of time outdoors and who look into LED screens to have their eyes protected from harmful UV and blue light.
Koh Liang Hwee (Dr), President Singapore Optometric Association.
This article was first published on Oct 17, 2014.
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