A persistently watery eye
Sometimes copious, persistent tears signal a common and usually harmless equine eye problem: a blocked tear duct.
Technically known as nasolacrimal ducts, these tiny passages allow tears to drain from the eye down through the nostrils. If the ducts become clogged with mucus or other material, tears collect and spill over the bottom lid of the eye.
To clear the blockage, a veterinarian will run a small tube up through the horse’s nose and flush saline through the channel. After a tear duct is flushed, it may never become clogged again, but some horses are prone to blockages and it may be best to simply leave them. When that’s the case, however, it’s important to protect the area below the eye against scalding with a thin layer of petroleum jelly and to use a mask against flies, which will be drawn to the moisture.