Lea test

The LEA Vision Test System is a series of pediatric vision tests designed specifically for children who do not know how to read the letters of the alphabet that are typically used in eye charts. There are numerous variants of the LEA test which can be used to assess the visual capabilities of near vision and distance vision, as well as several other aspects of occupational health, such as contrast sensitivity, visual field, color vision, visual adaptation, motion perception, and ocular function and accommodation (eye).

The first version of the LEA test was developed in 1976 by Finnish pediatric ophthalmologist Lea Hyvärinen, MD, PhD. Dr. Hyvärinen completed her thesis on fluorescein angiography and helped start the first clinical laboratory in that area while serving as a fellow at the Wilmer Eye Institute of Johns Hopkins Hospital in 1967. During her time with the Wilmer Institute, she became interested in vision rehabilitation and assessment and has been working in that field since the 1970s, training rehabilitation teams, designing new visual assessment devices, and teaching. The first test within the LEA Vision Test System that Dr. Hyvarinen created was the classic LEA Symbols Test followed shortly by the LEA Numbers Test which was used in comparison studies within the field of occupational medicine.

Among the array of visual assessment picture tests that exist, the LEA symbols tests are the only tests that have been calibrated against the standardized Landolt C vision test symbol. The Landolt C is an optotype that is used throughout most of the world as the standardized symbol for measuring visual acuity. It is identical to the "C" that is used in the traditional Snellen chart.

...
Wikipedia