Approximating Vizing's independence number conjecture

In 1965, Vizing conjectured that the independence ratio of edge-chromatic critical graphs is at most $\frac{1}{2}$. We prove that for every $\epsilon > 0$ this conjecture is equivalent to its restriction on a specific set of edge-chromatic critical graphs with independence ratio smaller than $\frac{1}{2}+ϵ$.