I'm so sorry your little guy is suffering and I hope he will feel better soon.
My concern is how you're describing him just 'laying around'. To me, that symptom points toward something other than his vision -- and I'd want a full blood panel done (incl testing for diabetes). Most dogs who lose their vision do freakishly well, so that's why I'm a bit worried that something else is going on with him along w/ the vision. If something else *is* wrong and it gets fixed, you may find afterward that he does really well w/ his vision loss. Of course, who knows, everything else may be perfectly fine and then you're right back where you are now.
My Wylie has a big cataract in 1 eye and now a new/smaller one in the other eye. A couple years ago we went to the Vet Ophthalmologist - that appt was $400. They do a really comprehensive eye exam (both eyes) that all takes around an hour or so; then they describe the options, one of which is surgery.
Please keep up posted
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