"When a smart and lonely charlatan is mockingly deceived by a criminal financier, she puts together a gang of female con-artists, to get the businessman’s financial empire to collapse."

After losing the money to pay for her daughters eye surgery to a ruthless con-artist , a visually impaired woman herself becomes a con-artist in order to prevent her daughter from suffering her own visually impaired fate.

Maybe like this?

When a visually impaired mother gets contemptuously betrayed on her daughter?s surgery money, she masters the art of the con to get the money back from the criminal businessman before the daughter ends up with the same eye disease.?

Somewhat clearer, but shouldn't her objective goal be to get her money back for her daughter's eye operation? She may want to take down the criminal as revenge -- but that's a bonus. Her primary goal is to get the money she needs for the surgery.

And "she must learn to become a con artist" is weak. Something like "she masters the art of the con" or "becomes a con artist" is stronger. The suspense in the story, the moment of truth, is not in the learning but the doing -- can she pull off the con? (Of course, she must learn but that builds up to the moment of truth.)