The Contact Lens is a key item in Paper Mario: The Thousand-Year Door.
After Mario accidentally step on Zess T.'s old Contact Lens, she blocks off the way to west Rogueport. Zess T. refuses to move until Mario buys her another pair. Mario must head into the nearby Item Shop and talk to the shopkeeper about his problem. The shopkeeper then puts in the order for Contact Lens and tells Mario he must wait a little while before they come in. After heading back into the Item Shop, Mario can then purchase the Contact Lens for 10 coins and give them to Zess T. A pleased Zess T. then heads back inside of her house allowing access to west Rogueport again.
- It should be noted that breaking Zess T.'s old Contact Lens can occur right near the beginning of the game (before Chapter 1). However, the Contact Lens would not be able to be purchased until before Chapter 3 as the plot requires the player to access west Rogueport only during that time.