A dogs swollen eye can mean many things. It may be a sign of an acute or chronic infection or it could be a symptom of a long-term or progressive disease in the body.
Other symptoms can sometimes be identified to help pinpoint any problems that may be contributing to your dog's swollen eye, and treatments may be directly applied to the eye with an ointment or eyewash, or may be given in the form of oral or other medications to treat any underlying disease. Treatment will depend upon what's causing the symptoms.
Allergies
One of the first signs of allergies or an allergic reaction to a toxin or insect bite may show up in the form of a dog's swollen eye. One or both eyes may swell in response to the allergy and other symptoms may appear, such as sticky discharge or redness of the eye or eyelid.
If you suspect an insect bite or common allergic reaction, you may wish to wait for about 24 hours to see if the swelling subsides. Otherwise, it may be recommended for your dog to receive medication or a shot to prevent infection or further symptoms. Tests may also be run to rule out any other conditions that may be contributing to the swelling.
Conjunctivitis
A dog's swollen eye could indicate conjunctivitis. Conjunctivitis is caused by inflammation in the mucous membranes of the eye and may result from bacteria, a virus or less commonly, a tick bite or other parasitic infection. This condition may be acute or chronic, may be accompanied by other symptoms, and could become severe if left untreated.
For chronic conjunctivitis, keeping the eye clean and clear of discharge can be very beneficial. Treatment options will depend upon what has caused the condition. Long-term medication may be required to treat a disease and keep conjunctivitis, as a symptom, under control. Eyedrops and antibacterial medications are commonly used to clear up redness and swelling associated with this type of infection.
Glaucoma
Glaucoma causes pressure within the eye leading to swelling with a cloudy appearance or significant redness. The pupils may enlarge and a dog's swollen eye, due to glaucoma, may require emergency care to reduce the pressure within the eye before permanent blindness occurs. Glaucoma can be caused by certain imbalances of the body's natural chemicals or inhabitants, such as yeast, and certain breeds of dog appear to be slightly more susceptible to this condition.
Viruses
Viruses, such as distemper and hepatitis, may cause dogs' swollen eyes, in addition to a plethora of other symptoms. Under these conditions, swelling may result from fluid accumulation, lesions, retinal detachment or inflammation. Certain types of testing can help to reveal which virus may be the cause of troublesome eye symptoms.
Other Conditions and Diseases
Often, a dog's swollen eye can help to indicate a more serious problem within the body. For example, hypothyroidism can lead to problems with the retina or chronic conjunctivitis. Blood or vascular diseases may be indicated by a dog's swollen eye, accompanied by hemorrhaging, retinal detachment or excessive fluid.