Causes of red eyeballs in dogs:

1. Conjunctivitis: It can cause extensive congestion and edema of the conjunctiva, and is often accompanied by a large amount of secretions on the ocular surface. .

2. Conjunctival hemorrhage: Usually caused by eye trauma, the conjunctiva is locally congested and red. This congestion has obvious limitations.

3. Corneal ulcer: When a corneal ulcer occurs, the corneal surface is usually accompanied by the growth of new blood vessels.

4. Third eyelid gland hyperplasia: The prolapsed gland is located in the inner corner of the eye. If the disease lasts for a long time, the gland will usually become congested and swollen.

5. Glaucoma: It usually causes redness of the white of the eyeball, sometimes bleeding in the eye, and pain in the affected eye.

6. Uveitis: The whites of the eyes will also become red, and blood may easily accumulate in the eyes. But the main difference with glaucoma is the difference in intraocular pressure, which usually increases when glaucoma occurs.

7. Kidney disease: It may also cause the dog’s eyeballs to turn red and his mouth to smell like urea.

8. Pyometra: A serious disease like pyometra in dogs can also cause red eyes.