Is lightning bad for your eyes

Its raining right now with lightning. Lots of lightning, I would say an interval of 1/2 second between each lightning.

I was looking at the lightning through my window for at least 10 minutes. Then I thought, could it be bad for my eyes?

No, in your situation, it is not bad for your eyes. It is not bright enough nor has any harmful elements that could pose any threat to your eyes.

No I don't believe lightning contains UV rays which are bad for your eyes.