Dr. Mark is a veterinarian. He works mostly with dogs and exotic animals.
Why Does My Dog Have Red Eyes?
There are some common reasons for red eyes in a dog. Many eye issues are mild and can be treated easily, but others, if left untreated, can and will become serious.
Below is a list of the most common causes of bloodshot eyes in dogs. If you choose to ignore some of these symptoms and issues, your dog may end up losing its vision. The good news is that a lot of these problems are easy to deal with if you act fast. The bad news is that some of these conditions are impossible to help if you wait too long. Get help now.
Common Causes of a Red Eye in Dogs
- Allergies (seasonal)
- Trauma (scratches, etc.)
- Foreign body
- Infection
- Keratoconjunctivitis sicca or KCS (dry eye)
- Cancer
- A serious eye problem like glaucoma
Classifications of Eye Conditions
A lot of causes of a red eye in dogs are treatable:
Allergic Conjunctivitis
If the exam and all of the testing is normal, your dog might be diagnosed with allergic conjunctivitis and sent home with an antibiotic/steroid cream. If he responds, you and the vet will need to find the source of his allergy, but it is very easy to treat if it becomes a problem. Don’t consider this a wasted trip—this is really the “best problem” your dog can have!
Eyelid Diseases
Sometimes a dog’s lashes will roll in and touch the eye. If this is the case, your dog can be treated with a cream to prevent infection, but eventually will need surgery to remove the eyelash and keep the eye from being constantly irritated. If the surgery is successful the eye will be fine and will no longer need any treatment.
Scratches or Trauma
As long as the retina (the nerves at the back of the eye) is not damaged, the scratch can be treated with an antibiotic cream. Some scratches are severe and the eye will need to be sutured closed while it heals, but some of them get better with treatment.
Foreign body: This is sometimes easy to deal with. The eye can be flushed with saline and the object is removed. Antibiotics are usually sent home to prevent a secondary infection, but after treatment there are no problems.
Infections (Bacterial or Fungal)
If it is a bacterial infection, the treatment has to be intense (sometimes every hour, at least every four or six hours) but it gets better in a few days. If it is a viral infection, like distemper, there are other more serious problems. For a fungal infection, the red eye will get better after the whole dog is treated.
KCS
If your dog is not producing enough tears to keep his eyes moist, a red eye is one of the signs. He will be sent home with a cream to increase tear production, but this is just a means to make him feel better. There is a surgery available to divert a salivary duct to his eyes, but most dogs will need to be treated for the rest of their lives.
Cancer
There are several types of cancer of the eye that can cause a red eye. The most common are lymphosarcoma and a mast cell tumor. The tumor can be identified in an exam if you take your dog in early, or if it becomes large you will be able to see it. The tumor will need to be biopsied to determine the type, and your vet will let you know the best treatment options.
Some eye problems can be diagnosed with the ophthalmoscope, some will require a culture and microscopic exam, and others will need blood work. If your vet suspects that your dog might have increased pressure, he will check the pressure inside the eye.
Will My Dog Get Better?
Since many of these diseases will respond to treatment early, you should do your best to get your dog to the vet as soon as possible. If you wait and see, the problem might go away. Or, your dog may end up blind. Think about it.
The eye is not something that you can diagnose at home. You can buy some physiologic saline and flush the eyes, just like you would your own, but your dog cannot tell you how much pain he is in, nor can he tell you whether flushing the eye is doing any good at all. Remember, these diseases are also painful. Think about your dog and do the right thing.
What Should I Do?
There are a lot of causes of a red eye or eyes. If your dog has been playing with the cat or is one of the breeds with protruding eyes, his eye may have been scratched and he needs medical treatment as soon as possible. (If his eye has been scratched, he will be squinting in one eye and will be in a lot of pain. I consider this an emergency and you should take your dog to your vet as soon as possible.)
Be a Responsible Owner
If both eyes are affected it is probably not a scratch or other trauma. Is it an emergency? You are your dog’s caretaker, so you really need to decide that for yourself. Being responsible for a dog is like taking care of a small child. The child cannot tell you how much pain she is in, nor can the dog.
When you take the dog in for an exam, the vet will examine the eye with an ophthalmoscope, a special tool that will allow him to examine both the surface and the inside of the eye. He might put some dye in the eye to check for trauma, and might also check the dog´s tear production.
Depending on what he suspects, he might need to take a swab from the eye and examine the sample under the microscope. If something more serious is suspected, your dog might need some blood tests.
Resources
Ofri, Ron, Clinical Approach to the Dog with Red Eyes, Proceedings on the 31st World Congress of the the Small Animal Veterinary Association, 2006.
This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.
Questions & Answers
Question: My puppys eye looks like it rolls up and turns completely pinkish red, then the black circle comes back down and his eye looks normal again. What is this due to?
Answer: If your dog has a prolapsed nictitating membrane, he is more likely to develop secondary eye infections. I can not tell you for sure without looking at it so you should take your puppy in for an examination by his regular vet.
Question: It looks like my dog has a broken blood vessel in the brown of the eye what could it be?
Answer: Do you mean the iris that is brown in many dog breeds? If your dog is bleeding into the eye, either into the front or back chambers, it needs to be examined.