When you close your eyelids your eyelids can protect your eyes from the strong and harmful UV rays from the sun.
So it's not bad to close your eyes and stare up into the sun with eyes closed for a few seconds.
However you should never stare at the sun without sunglasses or even with sunglasses because the sunglasses do not protect your eyes very good from the harmful UV rays.
Also it's bad to stare at the sun even with sunglasses as the sunglasses cannot block all the harmful UV rays that the sun puts out.
The suns UV rays are strong and can be damaging to your eyes if you look at the sun too long.
You could stare at the sun using a welding helmet and that would protect your eyes from the harmful UV rays that the sun puts out.
The sun could permanently blind you if you were able to stare directly into the sun for 100 seconds or less.
But staring at the sun without sunglasses or a welding helmet longer than a few seconds is usually impossible as your eyes will close the eyelids to protect them.
The time it takes for sun to damage eyes is 100 seconds or less of looking directly into the sun.
According to medical professionals blindness and permanent retinal damage can occur when someone looks at the sun for 100 seconds or less.
This is under two minutes but ultimately, how long it takes for eye damage and permanent blindness to occur depends on several factors, such as the dilation of the pupil and the sun's intensity on that specific day.
To go blind from staring at or looking directly at the sun you would have to stare at the sun more than a minute or two.
The suns rays are so powerful that your eyes will prevent you from staring at the sun for more than a split second.
If you try staring at the bright sun without any sunglasses then your eyelids will close and your head will likely drop or move away from the sun to prevent eye damage.
You can use a welders helmet if you want to look directly at the sun without damaging your eyes.