I had a barrel mare that I firmly believe was nearsighted. I had to give her 1/2 cc of ace orally just to warm her up before her run. She would shy at distant objects no matter how many times you took her around them. She would wash out just warming her up before a run at a show from shying from anything & everything. I had hauled her extensively & always won money once she entered the arena & was running. As it seemed if she was running she didn't have time to look for spooks she did perfect. When going slow her nickname was Rickashay!...lol...