Vision testing/training flipper

A vision testing/training flipper is a handheld device with two lenses mounted on a rotatable stem, allowing quick switching between plus and minus spherical powers. It is used by eye care professionals to diagnose accommodation disorders such as difficulty focusing, and can also be used by patients for self-directed vision training exercises to improve eye focusing ability.

This category of device is reusable and designed for repeated clinical or home use under professional guidance. Regulation typically follows general medical device rules for reusable diagnostic and therapeutic ophthalmic instruments, with classification depending on jurisdiction but generally falling under low-risk categories due to non-invasive, external use.