Snellen Ophthalmology Chart Pin
The Snellen visual acuity chart was developed in 1862 by ophthalmologist Herman Snellen. Snellen defined the “standard vision” as the ability to recognize the letters of the 20 line optotypes at a distance of 20 feet, hence the term "20/20".
Size: 1.5" tall
This soft enamel pin is cast from black nickel and filled with smooth epoxy filling.