24 July 2019
To reduce the risk of getting cataracts, people should cut down unnecessary screen time. Photo: Bloomberg
To reduce the risk of getting cataracts, people should cut down unnecessary screen time. Photo: Bloomberg

Why you should reduce exposure to digital screen

Light is a kind of energy in the form of waves and its visible spectrum has a wavelength of about 400 to 700 nanometers.

Beyond the visible spectrum between 10 nm and 400 nm is the ultraviolet (UV) band to which overexposure would be harmful to the human eye.

However, even within the visible spectrum, some colors are more dangerous than others.

Blue light, a wavelength of about 475 nm, could increase the risk of cataracts or macular degeneration.

Blue light emission is getting more prevalent in the digital era thanks to light-emitting diode (LED) display in electronic devices.

It appears as white light but it belongs to the blue light spectrum.

Cataracts tend to be age-related and mostly occur in varying degrees in elderly people 65 and above.

However, in recent years, there has been an increasing number of people in their forties seeking medical treatment for cataract.

Most of them have reported active digital screen time.

Fortunately, advances in cataract surgery have increased the safety and efficacy of the procedure.

The most common surgical technique is known as phacoemulsification — a process in which the eye’s internal lens is emulsified with an ultrasonic handpiece and aspirated from the eye.

The affected lens would be broken into pieces, liquefied and sucked out.

The advantage includes low invasiveness as the cut would be tiny and no stitches are usually required.

In recent years, there have been more choices of replacement lens as well.

The latest innovation is blue-blocking intraocular lenses which could provide extra protection to the eyes by filtering some blue light emission.

Nonetheless, prevention is always better than cure.

The best policy is to reduce unnecessary screen time.

This article appeared in the Hong Kong Economic Journal on Sept. 30

Translation by Darlie Yiu

[Chinese version 中文版]

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Fellow of the Hong Kong Academy of Medicine (Ophthalmology)

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