I am 28yr Old male have glasses for astigmatism .I remove my glasses only when i go to bed righteye -8.50 left eye -9.50 (they make me feel like I have tunnel vision). My question is why my vision becomes very blurry when my eyes are fatigued?? My eyes also do this shutter back and forth thing when I try to look at things up close. Its like my eyes involuntarily twitch from side to side when I try to focus on something small. Is it just muscle strainStrains ? The shuttering or twitching is kind of scary. The blurriness causes a problem when i'm driving. Thanks in advance san