A saline bag and iv-start kit, will fill your blood to max (which will remove grayed out color of your screen), and as you said you've got blurry vision, this is NOT due to blood loss. This is due to a value called "health". A saline bag will max-up your blood, but not your "health". That said, your blurriness will still exist. Currently the only way to regain "health" is to get the status effect "healing" which you get when you've eaten and filled up your water-supply to a sufficient level (and you've maxed your blood). IF you do not get your "health" up to the max, you may not have grayed colors on your screen, but you may just as easy die from one M4 shot, instead of 5 to the chest. EDIT: Very good explanation of what I just tried to tell you on the youtube videos below; 1:st
2:nd