When I stare at things too long, is it normal that everything in my sight suddenly reduce in size?

Sometimes, when I stare at things too long, or maybe it's my eyes being really tired, everything in my sight would reduce in size. Is that normal? I had this since really young, and this situation would take some time to go away. and during this time, I would sometimes feel like I loose my balance and feel a teeny tiny bit dizzy..

I had been trying to search other people having the same thing but I couldn't. Is that a disease or eye problem?

Thanks!