Foreign material such as grass seeds, dirt, and specks of vegetable matter can adhere to the surface of the eye or become trapped behind the eyelids. Dogs who ride in the open bed of a pickup truck and in the cars with their head out the windows are at high risk for getting dirt and debris in the eyes. Thorns, thistles, and splinters can also penetrate the cornea. This is most likely to happen when a dog is running through dense brush and tall weeds.
Signs of a foreign body in the eye are tearing and watering, blinking, squinting, and pawing. The third eyelid may protrude to protect the painful eye.
Examine the eye. You may be able to see dirt or plant material on the surface or behind the upper and lower eyelids. If not, the foreign body may be caught behind the third eyelid. In that case, the dog will need a topical eye anesthetic before it can be removed.
Treatment: To remove foreign material on the surface of the eye or behind the eyelids, restrain the dog and hold the eyelids open as described in How to Apply Eye Medicine. Flush the eye for 10 to 15 minutes using cool water, or preferably a sterile saline eyewash or artificial tears. To flush the eye, soak a wad of cotton in the solution and squeeze it into the eye repeatedly. If you have a bottle of artificial tears on hand, you can flush the eye directly from the bottle.
If the foreign body cannot be removed by irrigation, you may be able to remove it by gently touching it with a wet cotton-tipped swab. The foreign body may adhere to the cotton tip. Foreign bodies that penetrate the surface of the eye must be removed by a veterinarian. Restrain the dog from pawing at the eye while you drive to the veterinary hospital.
If the dog continues to squint or tear after the foreign body has been removed, have him checked by your veterinarian to see if the cornea has been damaged.