Well about the blurry vision I think you might need glasses? it wont hurt to check up on that.
As for the rest of it the concentration and memory I personally think it's due to your lack of proper sleep and I'm not a professional so I would suggest you go see one and check out what the core problem is. I hope you feel better soon
No way for me (anyone?) to say, but I think the first thing to analyze is your life style, particularly if there were any changes before the sleep problem surfaced.
I don't care to exahust my poor memory on good practices to get the body/mind clock adjuster to awake during "work time" and sleep during sleep time, which should be about 8 hours worth for most of us. Look up "adjusting sleep clock" comes to mind as a possible search string that might help find the recommendations. You can try the search here on medhelp first, but I'd also go to the Web for other sources.
You may find my thinking on the search here.