Damage to the eyes has a cumulative effect from light exposure. This has been demonstrated in the modern error by airplane pilots. After years of high altitude flight, it is not unusual for pilots to have eye damage. With constant exposure to welding arcs, eye damage to welders is also a concern. As we age, phototoxic exposure incidences accumulate.  Ultra-violet (UV) light damages the front of the eye and blue light damages the back of the eye.  The reason many of the names of eye diseases have the word age in them, like age-related macular degeneration (AMD), is from the cumulative effect over time.  Phototoxicity has several components: intensity, wavelength, and accumulated exposure.  One event of looking at an arc welder or one time in a tanning bed without any eye protection can be very damaging to the eyes.

Long term exposure to any toxicity can be damaging to health. Too much fluorine in the water over time, eating too much sugar and flour, drinking too much alcohol, not wearing your seat belt, teasing the neighbors pit bull, and other seemingly innocent behaviors will kill you given enough exposure. It is the identification of the exposure and risk versus reward that is difficult.  In the case of LEDs, there is such an advantage of power consumption; the people with control to make societal changes took the risk. After several decades of exposure to the Trojan Horse emitter of blue light, phototoxicity will eventually take your vision. The eye docs will tell you that it is just old age.  They have not considered the risk with the introduction of the pale blue horse. It is such a great thing to reduce power consumption and save you from sea level rise as the planet warms.  I say this is that stinky stuff falling out the back of the horse and money is king. 

It turns out that we have known about the dangers of too much exposure to blue light since the 1960s. Of course, we have known about too much exposure to UV light for much longer.  The electromagnetic spectrum is so interesting.  All the way from gamma-ray radiation to long radio waves for communication, the spectrum provides us many opportunities.  If you want to know more about light, I would suggest this lengthy article, Blue Light and Health. (You should just ignore his recipe of making blue blockers, but if you have the skill, enjoy.) Light is everywhere and does not appear to be an immediate threat, so just ignore the dangers, and ride the pale blue horse. After all, the LED has reduced the lighting cost of your monthly electric bill by ninety percent.  Surely that is worth the risk of blindness.  Our leaders seem to think that the reduction of carbon dioxide emissions to prevent sea level rise is more important than your eye sight. 

There are computer screens, cell phones, TVs, street lights, and now our general house lighting; all provides us with exposure to high energy blue light.  You should note here that many cities have reduced the amount of new LED street lights because it was affecting the sleep of its residents. Only by controlling your exposure will you be successful in protecting your eyes.  Of course, the simple thing to do is to wear blue blockers when inside.  However, with no blue light or too much blue light at the correct times of day, you may upset your circadian rhythms because of the lack of or over production of melatonin.  –Pandemic Survivor

Other Articles on Blue Light and Eye Damage (You must make up your own mind. When huge economic advantages are involved; individual health takes a back seat.)

Review of Optometry—The Low Down on Blue Light  https://www.reviewofoptometry.com/ce/the-lowdown-on-blue-light-good-vs-bad-and-its-connection-to-amd-109744
Prevent Blindness—Blue Light and Your Eyes  http://www.preventblindness.org/blue-light-and-your-eyes
Blue Light Exposed  http://www.bluelightexposed.com/#blue-light-and-macular-degeneration
UAB News—Debunking Digital Eyestrain and Blue Light Myths (of course, a university professor’s take) https://www.uab.edu/news/youcanuse/item/7258-debunking-digital-eyestrain-and-blue-light-myths