As long as he's in the same surroundings, you shouldn't notice any difference. The first Shetland Sheepdog I bought my wife went blind. She wouldn't believe it, even when I pointed out the frosty eyes. I finally moved one chair about two feet. Yep, he ran smack into it. It was a large padded recliner, so no damage to him other than a little bewilderment and I moved it back into the original place, but it proved my point to her.
Speaking of the Old Hen's dog, she got a reality check this morning. She headed out the front door with the dog and then noticed a coyote standing at the end of the driveway. She spotted it about the same time he did, and off he goes after it. He's a little bitty dog, and she starts screaming at him to come back, which luckily he did. She goes out with the 9MM now. I'd warned her years ago not to take him out without a firearm, and this made a believer out of her.