Blindness can vary greatly between individuals. Generally speaking, average vision is 20/20 (someone can see at 20 feet what most people can see at 20 feet). It can go up quite high, to 20/4000 or so, although at a high enough number, it isn't useful. At that point, it switched to Count Fingers (being able to count the number of fingers at a set distance), Hand Movement (being able to see a waving hand at a set distance), Light Perception (able to see shadows, bright lights and such) and No Light Perception (generally unable to see anything).

For the senses, it is better to think that the person uses them more, and that practice makes them better at it. I think a good analogy would be someone playing in an orchestra. They don't have better hearing than average people, but they've practiced enough to discern more details.

If supernatural powers are involved, you probably have a bit of leeway in how it is presented. I remember a story many years ago about a swordsman who had been blinded, and he learned to hone his hearing so he could hear the noise of muscles, bone and moving blood of his opponents.

https://kenshin.fandom.com/wiki/Uonuma_Usui

Another option as well is using echolocation. Some people make a clicking noise with their tongue, while some others use a mechanical device to make a click. With practice, people can become surprisingly accurate in locating (large) objects. And with enough practice, people can get pretty fast at it.

a) I am like your blind character in that I can only recognize sources of light.

b) So: when you describe your other characters and tell from their perspectives, you would emphasize what they see, in the blind character's case emphasize the other four senses. How does air taste on a clear day, on a foggy day, on a windy or rainy or snowy day. What is the exact onomatapia of leaves crunching or branches breaking, or a sword being drawn? What is the smell of blood? I can sometimes tell different people by shaking hands with them how someone's palm is cold, another's is warm, someone's palm smooth, another's rough.

It sounds like you're putting a lot of thought into your character work, which is great to see - I fall into the legally blind / visually impaired category and have some useful vision.

If would be totally reasonable / accurate for your character to have light perception and be able to detect bright lights, shadows etc

The only thing I wanted to add, that you will likely want to consider is how your character will navigate their surroundings.

In the real world some with enough functional vision are able to navigate independently with no aids but others (like myself) will use a cane. Another method is sighted guide, when we are guided by another person and of course some VI and blind folk have service animals.

I wish you all the best with your writing!

What I would suggest, in addition to doing the research you are doing now is to include a blind person or two in your group of beta readers. There they will be able to help you best avoid the type of offensive stereotypes that it is all to easy to fall into. I would offer to assist in this regard myself as I’m always happy to help other writers where and when I can and even more than usual for your specific situation.

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