"You traded the Eyeball Frog for the World's Finest Eye Drops! Hurry! Take them to Biggoron before they go bad!"
— In-game description
The World's Finest Eye Drops as they appear in-game

The World's Finest Eye Drops are a quest item from The Legend of Zelda: Ocarina of Time. Part of the quest for Biggoron's Sword, the World's Finest Eye Drops are obtained by giving the Eyeball Frog to the Lake Scientist in the Lakeside Laboratory. They must then be quickly delivered to Biggoron on the Death Mountain Summit. If Link does not deliver them within four minutes, they will spoil, and Link will have to retrieve another Eyeball Frog from Zora's Domain, to have more made by the Lake Scientist. They will also spoil if Link uses a warp song in an attempt to speed his progress (as will all timed tasks of the quest). When Link successfully delivers the eye drops, Biggoron will thank Link, give him a Claim Check, and go to work on making Biggoron's Sword.