I tell this story a few times a year about my cousin, Mike. When we were little he was always squinting in the pool. Weird face. I asked him why was he looking like that with his face. Well, he swam with one eye open and the other closed for as long as he could throughout the day. Then when the chlorine in the water became too much for his red eye in use, he would switch his squint and have a good, fresh eye available to resume the fun activities and swimming for the second half of the day.
So, don't close both eyes half way. Rather, do what Mike did. Close one eye all the way and save it for later!
But, we swam in the days and times when there were not swim goggles.