Yes, they can see through the mask. It’s called a fly mask. Flies like to drink the liquid from the horse’s eyes. This is not only uncomfortable for the horse, it can cause irritation that may lead to an eye infection.
An eye infection in a horse is treatable, but it’s challenging to even the most talented horse person. Owners should always consult with their large animal veterinarian for recommendations on treatment and safe ways to administer the medication.
Horses are prey animals and their eyes are vital. Not only are the eyes large, they protrude and are located on the sides of the head. This gives the horse an amazing range of vision. If your eyes were positioned and protruded like a horse’s, they would be on the sides of your head, like your ears are. You would look funny, but you’d be able to look straight ahead and still see anyone sneaking up behind you.