It sounds like the same disease that house finches are suffering, an eye disease called mycoplasmal conjunctivitis, which has spread throughout most of the house finch’s range. Despite the mortality caused by the disease, house finch populations have not decreased. Today, house finches are among the most common of backyard birds, and are found at bird feeders in every state in the lower continental U.S. The same is true for American goldfinches. They my be suffering from the disease, but it has not had a negative impact on their populations. There is nothing you can do to help the birds at your feeders.