So I had this whole long reply typed up and then it went 'poof!'...
First, do a search for ERU, Equine Recurrent Uveitis. Mooblindness is an outdated term so I avoid using it. ERU is the clinical term so I use that in my posts. :)
Second, ERU is a VERY expensive and painful disease. I realized that in daily pain-time supplements alone, I spend over $40/month in the summer and at least $25/month in the winter.
Some ERU horses eventually need their eyes removed due to pain/their type of ERU and that seems to run around $800+/eye. With this filly being so young, it seems like the likelihood of her eventually needing one or both eyes removed is pretty high (the older the horse is when diagnosed, the better "prognosis" they have).
I think there should be a mind blowing amount of info that you'll find when you search for ERU but feel free to PM me if you have more questions!
I don't think an ERU horse is right for MOST people but I certainly plan on having another during my life.
Here are a few of my favorite links: Equine Recurrent Uveitis: Information for the Horse Owner Blind Horse Care, Training, and Riding Merck Veterinary Manual Equine Recurrent Uveitis - Animal Eye Care Equine Recurrent Uveitis (ERU) - Appaloosa coat patterns, coat colour genetics and practical information for breeders of spotted horses - The Appaloosa Project
Also, you will see asprin or bute mentioned in those articles. Personally, I've had luck with a combo. I use bute for "real" attacks (ie, eye is squinty/swollen/tearing/etc), MSM at the "eyeball level" (32,000mg, double the arthritis dose) for daily management - it reduces inflammation and inflammation is our enemy, and a mixture of Devil's Claw+Yucca for days when she seems ouchy or her eyes look slightly swollen but it's not an attack-attack. During the summer, she gets the DC+Y daily because, even with a 90%UV blocking flymask, she's in a lot of pain due to the brightness of the sun.
The aspirin that will be mentioned, I've found to work nearly identically with MSM. However, I can get MSM cheaper and in greater quantities (Lacey goes through 16oz of MSM in about 2 weeks) so I go with that.