That's a tough question to answer. Unfortunately, there have been no developments in butterfly macular dystrophy, but it is under investigation. If there is actual bleeding in the macula, an injection of Avastin can be given to prevent further vision loss, but it has no effect on the damage already done. However, I would recommend taking Vitamin C, a B complex vitamin, zinc, vitamin E, selenium and a multi-vitamin. Many of our chronic diseases, specifically eye diseases, are the result of poor nutrition. For example, cataracts can be avoided until old age if the person takes enough vitamin C. Both vit C and vit E are antioxidants which allows the choroid of the retina to do its job, namely carry out the trash. The choroid allows immune cells to remove toxic dead cells from the retina which can cause damage. The eye is also one of the structures that require more vitamin C, like the brain, probably because it is constantly "taking out the trash." I'm not saying taking these vitamins will improve your vision (although one can hope) but it will prevent further damage.
Ophthalmology in America has made great strides in saving vision. I won't say we are the most advanced in the field, but we can hold our own. We have recently come to realize that things that go wrong in other parts of the body, will effect the eyes greatly and knowing this gives us an advantage.
I hope this helped you, and I'm sorry I couldn't have been of more help!