Should dog blindness after surgery be disclosed?

My dog went in for dental cleaning and had "a major extraction." She was on antibiotics before and after surgery and yet the eye specialist determined something from the anesthesia triggered blindness in her otherwise healthy eyes. When we signed the papers for surgery the only side effect or risk noted was death. A better quality of life or a peaceful death was something we could live with. We would have never chosen to have her undergo the procedure if blindness was listed as a rare side effect. They also didn't list trachea problems we had to return to have her treated for. Medicines for humans list all possible complications, do the same rules not apply to animals?