Kim Goodman from the USA has a unique ability to make her eyeballs protrude from her eye sockets by 12 mm (0.47 in). This measurement was taken by an optometrist in Istanbul, Turkey, using a device called a proptometer.
The proptometer measures the extent to which the eyeballs can bulge out. It is an accurate process that involves taking three measurements and averaging them to get the final result. Kim discovered her talent when she was accidentally hit on the head with a hockey mask.
Since then, she has been able to intentionally pop out her eyes as a remarkable skill.