The
Dark Side
of
Blue Light
By Denis Langlois
The sun provides our primary source
of blue light. And exposure to some of
those rays is good for us. It can, for exam-
ple, boost mood, alertness and reaction
time. But, as many people know, there
is a dark side to blue light.
The increased use of digital devices
that emit the high-energy visible light,
including smartphones, tablets, com-
puters and flat-screen televisions, has
only increased the prevalence of
problems associated with blue light.
Vision experts say the human eye is
good at stopping ultra-violet rays from
reaching the retina, but it’s lousy at
blocking blue light. In fact, almost all
12 EYE FOCUS February Digital 2018
blue light passes through the cornea
and lens and reaches the retina.
Children are even more sensitive to
the effects of blue light than adults. The
Canadian Association of Optometrists,
which is the national voice of optometry
in Canada and represents 85 per cent
of doctors of optometry, says the effect
of blue light exposure is cumulative,
meaning the “the total number of
exposure hours is what matters.”
Prolonged exposure can cause digital
eye strain, which can produce head-
aches, blurred vision and dry irritated
eyes, as well as health and potentially
serious vision problems.