The Importance of What You Can't See

I was never very good at anything besides making my master money. Being born without vision was something that had landed me in the hands of a greedy swindler who often sold me to nobles as something to display or show off to others because of my cloudy gray eyes. Each time he pretended I had no faults and made more and more money as noble after noble returned me for a partial refund due to my handicap, leaving my master with riches. However, after being sold over thirty times, I find myself with a new master...one who actually seems to want to keep me, but why?