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I would like to help you and your dog with this question, but need a bit more information in order to better assist you.
Since this happened, has there been any vomiting?
If you call his name, does he look at you?
Do you have a bright flashlight on hand?
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The above is given for information only. Although I am a licensed veterinarian, I cannot legally prescribe medicines or diagnose your pet's condition without performing a physical exam. If you have concerns about your pet I would strongly advise contacting your regular veterinarian.
You can use scent to help Chava to know where things are - for example, put a Glade solid at the top and the bottom of the stairs in order to let him know that there is danger there. He will quickly learn that if he comes close to a Glade solid, it means there are stairs nearby!
You could rub a dryer sheet down the legs of your bed and the tables, so he can smell where they are.
Use bells on the door so that he can find it easily, he can use his nose and ears to help him get around.
Here is a link to more information on how to cope with a dog without vision: