The meaning of Justice Is Blind means that Judge, Jury etc are all impartial and Objective.
For example if you were to be a relative or friend of the Judge the Judge would still have to give you a fair trial and not give you any special privileges just because you're a friend or relative.
The Justice is blind means that the Justice sees no race, color, etc in deciding on the verdict.
The Judge and Jury has to follow through with the law and give you a fair trial whether you're black or white etc.
However while Justice is supposed to be blind in every courthouse that is not always the truth.
Some Judges will make decisions based on the race of the person, how they are dressed etc.
I've been in a court where a Judge made a decision of a custody battle because the parents were not dressed up fancy enough.
That is no reason to make a decision on the parents being fit enough to be parents.
The judge decided that since they didn't come dressed in suits and fancy clothes that the child would not be returned to them at that time.
So Justice is not always blind.