UV380 sunglasses block all light with wavelength 380nm or lower. This is in contrast to 400nm sunglasses, which block all light with wavelength 400nm or lower.

While I have no doubt that wearing 400nm sunglasses is good for protecting eyes against UV damage, I'm not sure about 380nm sunglasses.

According to this article, wearing unsuitable sunglasses can actually cause more damage than wearing none, because they make pupils dilate. While that specific article does not state that UV380 sunglasses are inadequate, this one mentions the following:

But, while the light radiation from 380 nm to 400 nm may not contain as much energy, it is also the only UV light that makes it all the way to the retina.

This seems to imply that 380nm to 400nm light somehow penetrates the eye better than lower-wavelength light, and that only UV400 sunglasses offer adequate protection.

So, the question remains, is wearing UV380 sunglasses helpful or harmful to the eye?

Since I do not have access to scientific literature in this field, I am asking this question here hoping that someone could share any relevant studies or provide an expert review of the literature.

PS: I am aware that this question is near the borderline of what is on-topic for this site. However, I believe it is within scope since I am interested in the biology underlying the effects of 380nm to 400nm light on the eye.

There are two categories of sunglasses: UV380 sunglasses block all light with wavelength 380nm or lower, while UV400 sunglasses block all light with wavelength 400nm or lower.

This made me wonder, what are the physiological effects of retinal exposure to the 380–400nm band of light, which is not covered by UV380 sunglasses?

Also, assuming that the 380–400nm UV light does cause eye damage, does any potential pupil dilation caused by the dark tint of such glasses have an effect on the amount of damage caused?