Good evening - I'm Dr. Sara - I'm a licensed veterinarian who works exclusively with dogs and cats. I'm sorry to hear that Dino has had trouble with his eyes.
Based on your description I'd be most suspicious of cataracts in those eyes. Cataracts are a progressive opacification of the lens, which is right behind the pupil. It usually can be seen as a white, gray, or blue color to the pupil which used to be black. Cataracts can sometimes come about fairly quickly like you noticed. Another thing that can happen quite suddenly is a disease called sudden acquired retinal degeneration or SARD. in SARD, the retina suddenly stops working, causing a sudden onset of blindness. There's no known cause for SARD, and unfortunately no treatment. In any case with a drastic change in vision like this it's a good idea to have your pet examined by the vet to be sure there's nothing else going on. For instance, sometimes vision loss can be caused by glaucoma, which is very painful and should be managed. Cataracts developing quickly can be a sign of diabetes, so it's important to consider some senior blood work to check for "whole body" diseases. What questions can I answer for you?