Japanese Vision Test
This chart - or some iteration of it - is the standard Japanese Vision Test, also known as a Landolt C, a Landolt ring, and a Landolt broken ring test, developed by the Swiss-born ophthalmologist Edmund Landolt (1846 - 1926). I take them regularly - as recently as Friday, April 9, 2021. I will take another on June 25, too, I think. The object is simple. The task of the tested person or patient is to decide on which side the gap is - which direction the gap in the letter C is: left, right, up or down. The size of the C and its gap are reduced until the subject makes a specified rate of errors. It’s a conveniently easy test for a foreigner to take in Japan if his language proficiency is retarded.