State and central governments are pulling out all stops in their efforts to promote LED (Light Emitting Diodes) lamps both inside the homes and outside. However, experts caution that LED lighting if not installed in moderation, could cause serious damage to the health of human beings.
Prolonged exposure to blue light, which is 10% more in LED than in CFL lighting, will lead to eye strain, and vision problems, Lighting Designer and Educator Anil Valia said, during his keynote address in a debate organised by the Institution of Engineers here on Tuesday. The CFLs contain about 25% of harmful blue light and LEDs contain about 35% of the same. The whiter the LED, the higher the blue light proportion, he mentioned.
Blue light affects the back of the eye, and precipitates Age-related Macular Degeneration, which causes irreversible vision damage. Ringing a caution bell, Mr. Valia said apart from LED light, excessive exposure to gadgets such as mobile phone and computer screen too could cause blue light exposure.
Chronic exposure to blue light at night could further interfere with the circadian rhythm (body clock) by lowering the production of Melatonin, the hormone that regulates sleep.
“Taking a break of 20 seconds from digital gadgets every 20 minutes, and looking away focussing on something 20 feet away will help maintain comfortable vision,” Mr. Valia said, even while citing the United States Department of Energy’s claim that LED lights are no more harmful than any other lighting. However, one should ensure that the lighting products meet the photobiological safety standards prescribed nationally and internationally.
Flicker and glare, more in frequency and intensity are one more problem associated with poorly manufactured LEDs.
Poor quality drivers used with the LEDs with a view to economise on cost, lead to flashes even after being switched off.
Flicker Index (FI) and Modulation (Mod%) should be checked for flicker frequency, and Unified Glare Rating should be verified for glare effect.
The antiquated technology used in lighting, however, is now changing with research in the fields of Chronobiology, Photobiology and Scotobiology determining how environmental light directly impacts the human body and brain, Mr. Valia said. The LED streetlighting too has its drawbacks, what with the doctors from the American Medical Association issuing warning two years ago that the white LED light is five times more effective in suppressing melatonin than the high pressure sodium lamps which give the same light output.
For streetlighting and other outdoor installations, the AMA recommended lamps with 3000 Kelvin or lower correlated colour temperature (CCT).
On the other hand, blue light could be beneficial when it comes from the Sun, as it gets diffused in the atmosphere and stimulates the retinal ganglion cells, thereby improving the biorhythm.
Mr. Valia called for ‘human centric lighting’, and strongly recommended that Bureau of Indian Standards should also include lighting parameters for biologically effective light.
