Why is my 1-year-old Mastiff suddenly blind in his right eye?

This is an emergency. Your dog needs to be seen by a veterinarian right away. Sudden loss of eye sight can be caused by many conditions, inherited/congenital eye disease, tick borne disease (Ehrlichiosis), diseases of the retina, SARDS (usually in older dogs), Inflammatory, autoimmune, or allergic causes and many more. Please take Buddy to a veterinarian now.

This is a medical emergency, and Pirata needs to see a vet right away. He could have suffered a seizure that has left him completely blind, he could have progressive retinal atrophy, or he could have diabetes causing the blindness. He needs to see a vet now in order to have the best chance of having his sight restored. Please bring him into a vet now.

This is a serious concern and you should take Gunner to a vet ASAP. He may have an infection, tick borne disease such as ehrlichiosis (I have seen sudden blindness caused by Ehrlichia canis) or a problem with blood pressure or ocular pressure. Blood work and a thorough veterinary exam should reveal the cause and then timely treatment can be initiated depending on the diagnosis,

Poor Roxy! This whiteness of her eye could be caused by a severe eye infection, injury to her eye, cataracts, or glaucoma. I would have seen by a vet immediately. The eye is such a delicate and important structure that any problem with it is considered an emergency. That's because leaving it untreated can lead to permanent vision loss. I would take Roxy into an ER vet or find a vet on call to see her now so her eye can be examined, diagnosed, and treated.

It sounds like Smudge is having issues with her vision. I would recommend that she be checked out by a vet to test this and see what could be the cause. There are many, many potential causes, including high blood pressure, tick disease or other infection, autoimmune disease, trauma, cataracts, among others. A vet will do a thorough physical exam, medical history review, and ocular exam. They may need to refer you to a veterinary ophthalmologist who may be better equipped to asses Smudge’s vision.

I strongly recommend you seek referral to a specialist ophthalmologist, it looks like there may be increased pressure or glaucoma which is very painful. It may be rarely associated with tumors but there are many other possible causes

Dogs can develop blindness secondary to disease of the brain (central), eye (peripheral) or secondary to systemic disease such as elevated blood pressure or Cushing's disease. If she is able to see now, she may not have been truly blind before or just had trouble seeing at night. A full examination would be needed to help to determine the underlying cause. In the meantime, observe her closely and make notes including changes in behavior, bumping into things, changes in eyes, changes in urination or defecation, appetite and take this information with you to your veterinary appointment.