THE HISTORICAL EVOLUTION OF VISUAL ACUITY MEASUREMENT

August Colenbrander, MD--San Francisco

This 8 page document retraces important historical steps in the evolution of visual acuity measurement.

Some proposals were dismissed when first proposed and accepted a century later.

Three principles of today's standard: non-serif letters, proportional spacing and logarithmic progression were proposed by John Green in 1868. They were ignored at the time.

A century later, when Bailey and Lovie proposed them again and the National Eye Institute incorporated them in the ETDRS protocol, they have become a de-facto standard.