Yes. Take him to the vet.

Dogs are good at hiding any pain or discomfort they may have.

I agree with harebell that a visit to the vet is in order.

Take him to the vet. At his age it is probably cataracts that got worse quicker than your vet expected, but best to be certain.

With all his health problems, he should be seeing the vet for any changes you notice. Physical changes can move much faster than you can imagine.

Possible glaucoma, but that is very painful so you would notice if he had discomfort. Glaucoma came come on suddenly and needs treated asap.

tumor, stroke, glaucoma, seizure, etc. etc.

If its a pressure issue (glaucoma), there are drops that can be administered to possibly reverse the problem and prevent it from happening to the other eye. I would get it checked.

Since your vet has already determined your dog has cataracts that could be the reason for him not seeing out of the one eye. Since three months have passed that would be enough time for a mature cataract to restrict vision. As noted by another poster glaucoma could also be an issue. This is very painful though and you would notice the dog squinting or pawing at his eyes. Is there any discoloration to the lens of the affected eye?

At any rate another trip back to your vet would be highly recommended.

Thanks for the advice. I have made an appointment and will be taking him to the vet in the morning. Will post after appointment.
Debbie

The vet said it was a cataract. Don't know with his condition if he will be able to have it removed. Have to take him to a specialist for a consultation. Thanks for all you help.
Debbie

I'll keep your dog in my thoughts for a good outcome at the consultation.