I have noticed, that sometimes i close one of my eyes when reading an sms when i am without my glasses. i this a bad habbit? i wear glasses constantly

Maybe: This is probably because one of your eyes is "stronger" than the other. If you don't do this too much, it is probably not a big deal, but make sure you have a recent eye exam to check if there is anything wrong with your other eye.

Eye closure: Eye closure while reading does not damage your eyes in any way. If it helps you to read, feel free to do it.