Surely the light from the sun is a much more damaging? Not to mention computer screens have existed for decades in some form now. I understand the connection with sleep, but Im not sure how much it really damages the eyes compared to other light sources.

Or course sun'rays are damaging, and it is why sunglasses exist. But if you are in front of a computer screen for 7/8 hours a day, you are exposed to blue LEDs which, unlike green and red LEDs are also damging for the eyes.