This was borrowed from Deer Creek Equine Clinic's FB page. I thought it was useful to know.....
“Since horses are prey animals their vision plays an important role in being able to see predators and take flight. That is why their eyes are set on the sides of their heads which gives them almost 360 degree vision. They cannot see a short distance directly in front and directly behind them. The number one safety rule when around horses to always speak to them when approaching them from behind and to come to the side of them when approaching from the front. There is a moment when negotiating jumps, narrow bridges, etc., that they may be doing it "blind" briefly. However, their retina is quite large giving them very good peripheral vision, so a subtle turn of the head allows the horse to focus in on an object.”
Until we meet again
“Saving the Planet One Horse at a Time”™