Sunglasses do not protect eyes from e-displays

FILTER::Most sunglasses can only block out ultraviolet rays, but there are photochromic lenses that can block out ultraviolet light as well as blue light, an ophthalmologist said

By Lo Pi and Sherry Hsiao  /  Staff reporter, with staff writer

Tue, Sep 11, 2018 - Page 3

Sunglasses do not protect people’s eyes from the blue light emitted by electronic devices, a Kaohsiung-based ophthalmologist said.

Some light, such as infrared light and ultraviolet light, are invisible, while others, such as red, orange, yellow, green, blue and purple, are visible, Bright Eyes Clinic director Liang Chung-ling (梁中玲) said.

Blue light is a stronger type of visible light that can pass through the cornea and lens and arrive directly in the macula, damaging photoreceptor cells and resulting in early onset of macular degeneration, she said.

Excessive viewing of electronic devices at a close distance is the main reason Taiwanese are developing myopia — or nearsightedness — at a younger age, she said, adding that high myopia is a major cause of blindness.

Sunlight and blue light from LED lights are both stronger than the blue light from electronic displays, she said, but added that while people usually do not look directly at sunlight or LED lights, the blue light from electronic devices directly enters the eyes, causing long-term damage.

Some people think that wearing sunglasses while using electronic devices can reduce the brightness of screens and protect their eyes, but that is incorrect, she said.

Most sunglasses can only block out ultraviolet rays, she said.

Glasses that do reduce blue light exposure have a special coating that reflects 20 to 40 percent of blue light, she said, adding that yellow-tinted lenses can also filter out blue light.

Photochromic lenses that block out ultraviolet light and blue light simultaneously are on the market, she said, adding that the lenses can be used indoors and outdoors.