Optical Prism recently asked Dr . Kirsten North , a policy consultant at the CAO , to shed some light on blue light and how people can protect themselves .
Q . In layman ' s terms , please explain what blue light is and where it comes from .
A . Blue light is defined as visible light ranging from 380 to 500 nanometers ( nm ). It is found in sunlight , indoor lighting ( such as LEDs and compact fluorescents ) and screens ( phones , tablets , computers and television ).
Q . Why is exposure to blue light potentially dangerous ?
A . Very little blue light is blocked by the human eye . Blue light is harder to focus and can contribute to eye strain . It is also a trigger for melatonin production and , if exposure happens late in the day , it can deregulate sleep cycles . Blue light has been linked to cataract formation and macular degeneration .
Q . Are optometrists concerned that , with the increase in digital device use , more and more people will experience vision problems related to blue light ?
A . Yes , this is one of the many reasons that the Canadian Association of Optometrists ( CAO ) collaborated with the Canadian Ophthalmological Society to develop the screen time guidelines . The guidelines can be downloaded at : tinyurl . com / y758fley
Q . How can people protect themselves from the potentially harmful effects of blue light ?
A . Experimental evidence has suggested exposure to blue light in the 470-490nm range may be less damaging compared to blue light from 400- 470nm . Development of LEDs with a peak emission in the safer range may represent an important advancement for ocular health .
Blue light exposure in younger people should be monitored and controlled . Over time , accumulated damage from blue light exposure can increase the likelihood and severity of age-related eye conditions such as macular degeneration and cataracts .
A healthy diet , high in leafy green vegetables and colourful fruits , may help to increase the levels of the
“ A HEALTHY DIET , HIGH IN LEAFY GREEN VEGETABLES AND COLOURFUL FRUITS , MAY HELP TO INCREASE THE LEVELS OF THE PROTECTIVE PIGMENTS IN THE RETINA AND MITIGATE SOME DAMAGING EFFECTS OF BLUE LIGHT .
” protective pigments in the retina and
mitigate some damaging effects of blue light . Good sleep is essential for attention , learning , mood , and general well-being .
The effects of blue light on the sleep cycle may be minimized by :
> Avoiding bright screens for two to three hours before bedtime ;
> Seeking some outdoor light exposure in the early hours of the day ;
> Limiting screen time to no more than two hours per day for children aged 5-18 , one hour per day for children aged 2-5 and avoiding it completely for children under 2 years of age .
EYE FOCUS | February Digital 2018 13