UGH! HAte it when these things happen and hate the decisions that have to be made. Never had a blind horse in my 22+ yrs of horse ownership, but have had to make those terrible decisions time and again. I had a beautiful gelding that went lame from a hereditary disease by the time he was 10. He was the best baby/kid raiser I had for my kiddos, and also the best buggy horse I ever had. I got him when he was a yearling, trained him myself, and loved him until the end. He was best friends with my older horse who at 25, was losing the battle with old age. I had decided that when it was time for one of them to go, the other would go with him. My older horse lost the luster in his eyes and I made the humane decision to end it. I buried them 10 foot deep in the middle of my garden.
My experience with blind horses (through two friends who chose to manage them for a few years - both horses met a bad fate, sadly) dealt with a lot of upkeep issues including wrecks with fences, separation anxiety from buddy horses, weight loss due to stress, colic and ulcers due to stress and both admitted their horse's quality of life was very poor prior to euthanasia. One horse severed a leg while panicking trying to get to a buddy horse she thought was on the other side of a fence (but wasn't) and the other developed infections in the eye due to equine recurrent uveitis and had to have one eye removed, and when the other became as bad as the first, the owner chose euthanasia. The mare was in horrible pain over the last year until she could finally be allowed to cross the rainbow bridge.
Ultimately, it is your decision. You shouldn't feel guilty about choosing euthanasia or for continuing to try to manage her with her blindness. If you choose the latter, just make sure you do the best you possibly can with what resources you have, and then in the end you'll be able to rest easier. The guilt of having to make a decision like this eats at our hearts and souls and in the end, you can only be comforted by the fact you did the best you could do.
