How much is your eyesight worth to you?

Spark Therapeutics recently launched a pioneering new drug that can improve the vision of patients with a rare hereditary form of vision loss. That’s not the only thing pioneering about this drug, called Luxturna. Its price is, too. Spark announced this week that treatment will cost $850,000 a patient. “We believe that price reflects the type of life-altering value we’re seeing with Luxturna in clinical trials and will allow us to build on revolutionary science,” Spark Chief Executive Jeff Marrazzo told The Wall Street Journal.