Disability is a spectrum
Being a person with a disability doesn't mean one looks a certain way or has the same abilities as someone else with the same or a similar disability. It's one reason why you'll hear about people with blindness or low vision. Various causes of blindness can play a role in how much of one's vision is affected, as well as many other factors. Some people can make out light or shapes and some have total blindness, and there is no particular look or characteristic that is the same for all of them. Things like color contrast can assist some folks with low vision and others will use a screen reader.
One recent example of this is Paul Castle, who was recently denied access to a restaurant with his service dog, because the staff didn't think he looked blind. "People really underestimate the blind community, our ability to use our
other senses," he said. "Just because sight is gone, and in my case,
mostly gone, does not mean that I am not alert and aware of my
surroundings, and have the ability to do things very capably."