By JoAnna Pendergrass, DVM
A dog’s eyes function a lot like our own. When normal and healthy, a dog’s eyes will take in light and transform it into images, like a food bowl or favorite toy. If those eyes become red and irritated, though, they can cause major discomfort and possibly not function very well. If your dog’s eyes are red, it will be important for you to know what’s causing the redness and what you can do to treat your dog’s eyes.
Causes of Red Eyes in Dogs
Dogs’ eyes can become red for a number of reasons. Common causes include:
- Dry Eye (Keratoconjunctivitis sicca): Dry eye occurs when the eyes don’t produce enough tear film. Without tears to keep the cornea moist and free from debris or infectious agents, the cornea becomes dry and inflamed. This inflammation is quite painful and makes the eyes look red. Dry eye has many causes, the most common of which is immune-mediated adenitis, which damages tissue responsible for forming the watery portion of tear film.
- Pink eye (Conjunctivitis): Pink eye occurs when the conjunctiva—the moist, pink tissue that lines the inner eyelids and front of the eyes—becomes inflamed. This inflammation causes redness. Environmental irritants like dust and pollen can cause pink eye.
- Cherry eye: Dogs have a third eyelid that normally stays hidden. Some dogs have a genetic disorder that weakens the ligaments holding this eyelid in place, causing the eyelid to pop up and look like a cherry in the inner corner of the eye.
- Corneal damage: Anything that can damage a dog’s cornea can cause eye redness. For example, if your dog is running through tall grass, a grass stalk can poke your dog’s eye and cause damage and irritation.
Other Eye Symptoms
Along with redness, you might notice some other eye symptoms:
- Mucus discharge
- Excessive blinking
- Swollen conjunctiva
- Constant eye rubbing
- Increased eye-watering
- Corneal scratches or scars
- A foreign object stuck in the eye
- Green or yellow discharge, indicating infection
What to Do About Eye Problems in Dogs
Eye problems in dogs are not always an emergency but do require prompt attention. If your dog’s eyes are red, call your veterinarian and try to schedule an appointment for that same day. When you schedule the appointment, provide a brief history of the redness, including when the redness started and what other symptoms you see.
Do not try to diagnose and treat the eye redness yourself. Your veterinarian has the expertise and equipment needed to properly examine your dog’s eyes and determine what’s causing the redness.
Also, do not delay taking your dog to the veterinarian. Eye problems can progress to something more serious—and possibly painful—if not treated promptly. The sooner your dog can be seen by your veterinarian, the better.
Diagnosis and Treatment
Your veterinarian will conduct a detailed eye exam, during which she will identify which parts of your dog’s eyes are red. If your vet suspects corneal damage, she will add a few drops of a fluorescent green dye on the cornea to see if there are any corneal scars or scratches.
If dry eye is a possibility, your vet will perform what’s called a Schirmer tear test to estimate the level of tear production. She may also take a small sample of watery fluid from your dog’s eyes to determine if there is an underlying bacterial infection.
Your veterinarian will recommend treatments according to what’s causing the eye redness. For example, if your dog has dry eye, your veterinarian will prescribe medications like cyclosporine, which stimulates tear production, or artificial tears. If your dog has cherry eye, your veterinarian will surgically anchor the third eyelid into place. Other treatments include anti-inflammatory medications and antibiotics.
Eye medications are typically formulated as ointments or eye drops. Before you leave your appointment, make sure you understand how to properly administer the medications that your dog will need. If you have not given your dog topical eye medications before, ask your vet to demonstrate how to do so.
Keep in mind that not all dogs like receiving eye drops or eye ointments. You may need to be patient with your dog and allow extra time to give the medications.
Living and Management
How you manage your dog’s eyes after initial treatment will depend on what caused the redness. With dry eye, for example, you will need to regularly administer the topical eye medications, clean your dog’s eyes with a prescribed eye wash, and take your dog to followup appointments every six to 12 months.
If dust and pollen are irritating your dog’s eyes, then your vet may recommend that you frequently dust your home or limit your dog’s time outside when the pollen count is high. Cherry eye can recur after surgical treatment, so you will need to monitor if your dog’s third eyelid pops up again.
Your veterinarian will help you determine which management strategy will work best to prevent future eye redness.