I had my vet come in and do a pre purchase exam on her. Because of my history with J (my girl) I was most concerned with eye issues. The vet took a look and saw some damage that appears to have happened in her past. She has vision in it but because she appears to have some Appaloosa in her breeding...and she is a roan...the vet said that the damage could have been due to recurrent uveitis. Her eyes otherwise are in good shape. I am terrified of getting another horse and having them go blind on me...SO would this be a deal breaker for you? Would you let her pass by on a chance that she could wind up with "moonblindness"? She has such a great disposition and I really did "bond" with her...I would hate to pass her by on a possibility that could never come to fruition.
While I am obviously bias, it's from a good bit of personal experience, and I would say not to let *the possibility of her going blind in the future keep you from buying her, especially since you say you felt a connection. If the horse is healthy otherwise and you think she could handle going blind (which if she's that calm, she likely would be fine), then I’d say go for it, as they can make excellent horses. Dealing with moon blindness can be hard and unpredictable, so I can understand where others are coming from.
I'm sorry about your mare, but the parts I bolded is what I'd think hard about. Just the possibility of going blind or even being blind does not always mean heartbreak for you, and I would not let that alone dictate your decision. I would not let her pass solely because she might
go blind in the future, especially if you like her personality. The gelding I ride and a few of his pasturemates are blind and have been for several years, but they're all wonderful, helathy horses.
I don't mean to imply that you should always buy the horse and ignore the eye issues because some don't adjust, I just want to make sure you're aware that horses can adjust just fine to being blind (for example the horse Cherokee in my barn here), and that I wouldn't let a fear of that blindness hold you back if you truly feel a connection with this new mare. Being blind is typically not a death sentence, it is just an adjustment, and it does not have to end in heartbreak!
Regardless of the decision you make, I just hope you'll consider this and not pass her up solely for that reason. If you decide it's not worth it to you to take the chance given your past experience or that you can't handle owning a blind horse should she go blind, that's fine, I just wanted this information to be there for you. Best of luck with her or in your search if you move on.