01/09/2025
Blue blocking lenses have been quite a subject over the last number of years and many lens companies have developed coatings and materials which supposedly block blue light.
Why do we want to block blue light? Well, the most publicised reason has been (so the theory goes) that now so many of us are screen based a lot of the time, it has been proposed that the blue light emitted from our screens somehow causes eye fatigue and potentially macular degeneration. Given the low level of light emitted from screens and LEDs the evidence is very poor that blue light can really have a measurable effect on the issues stated above.
HOWEVER, there is another issue regarding blue light exposure, particularly after sundown which has been less publicised, but has much more evidence to back it up. I'm talking about melatonin production. Until the advent of screens, fluorescent lights and LEDs, humans NEVER experienced blue light after dark.
What has been discovered is that melatonin (the hormone which makes you sleepy) production can be reduced by as much as 70% with exposure to indoor blue light in the evenings.
This can make it much harder to go to sleep and stay asleep.
The trouble with most lenses marketed as 'blue blocking lenses' is that they do not block the wavelength which blocks melatonin production. No clear lens can do that, so the lenses must be amber to red in colour and block the 450 to 500 nanometer range.
In reality, we probably should all be wearing effective blue blocking lenses after dark unless we are not exposed to LEDs and screens in the evening.
