Some studies have shown previously that exposure to LED (light emitting diode) light, especially the shorter wavelength of white light (blue light) can cause damage to the retina induced by oxidative stress. The other sources which emit blue light are computers, tablets, television screens and mobile phones. LED lights as well as the use of digital devices has increased in the last few years and its use is likely to be much more in the future.

A recent study conducted in the UK assessed many sources for the amount of blue light they emitted. The amount of exposure to blue light was compared to the recommended international exposure limits. It was also compared with the exposure of blue light received form looking at the clear blue sky.

The study found that none of the sources were found to emit blue light which could damage the eye even on long exposure. The researchers also concluded that of all the sources tested, looking at the clear sky produced more exposure to blue light than the digital devices and LED light.

This is in contrast to older studies which indicated that prolonged exposure to blue light could damage the retina of the eye. Apart from retinal damage, the effect of blue light on circadian rhythm (internal biological clock) is also important as it disturbs the sleep cycle if we are exposed to blue light in the evening and night time.

To establish the effect of blue light on retinal health, more and larger studies need to be undertaken which involve humans rather than animals.

1. Retinal light toxicity
2. White Light–Emitting Diodes (LEDs) at Domestic Lighting Levels and Retinal Injury in a Rat Model