Please help! -Weak Vision

Hey guys, I'm looking for advice/tips to strengthen my vision. I'm in college studying to be a graphic designer and my eyes get tired of looking at screens and then they get weaker at just seeing in general. I had double vision and was admitted to the ER around October last year and began treatment in December. The double vision stopped pretty quick after being released and I got 90% of my vision back but I had taken a break from school during the winter. My vision is declining again and I worry about another relapse. As a college student almost graduating with a degree in graphic design, it sucks to be going through vision being really weak and not seeing details on the computer/mobile//tv screen. Any advice on ANYTHING i can do to strengthen my vision? Please help!