Will long-term usage of computer cause cross-eyed?

I am a graphic design. Everyday I spend long hours staring into the computer screen. Now after many months, my eyes are starting to feel strained easily and it feels 'tighten'.

I do not have crossed-eyes in the past, but now I noticed that my eyes are slightly crossed!

My question is, if I continue to like this, will it cause my eyes be crossed permanently?? Are there any such cases of long-term usage of computer that cause one's eyes to be permanently crossed?

Thank you.