Do you normally have anything wrong with your eyes ie: short sightedness etc. It sounds like a healing symptom to me. It wouldn't be a nutritional thing, not in 4 days. And did the symptom stop, when you resumed your normal diet? I've heard stories of people's eyesight getting better after a fast.
Water only on this site, no lemon or supplements. Seasalt is good for normalizing blood pressure,imho, but not to take whilst fasting, although the fast will take care of your problem anyway.
You have already done 4 days before, so it should be easier this time, famous last words lol.