id	author	title	date	pages	extension	mime	words	sentence	flesch	summary	cache	txt
hindsight-4043	Editors, Hindsight	Vol 29, No 2 (1998)	1998	8	.pdf	application/pdf	4752	117	47	An early system for visual acuity chart letter sizes: Number 2 In the late 19th century and early 20th century various systems had been proposed and were being used for designating visual acuity and for the progression of letter sizes on visual acuity charts. This led to a bit of confusion and to too much diversity in the expression of visual acuity and necessitated certain calculations in order to establish a comparison between the fractions furnished by different scales.	cache/hindsight-4043.pdf	txt/hindsight-4043.txt