id	author	title	date	pages	extension	mime	words	sentence	flesch	summary	cache	txt
hindsight-3554	Editors, Hindsight	Vol 9, No 1 (1978)	1978	16	.pdf	application/pdf	7065	325	61	-6- In his collecting of all the writings about spectacle lenses during the three centuries between their invention and I1 Porta's publication Ronchi has found three short passages in XIV century, not a single one in XV century, and four mentions in XVI century, and every time to condemn the use of lenses and to confirm their deceptive character. Owing to the present widespread interest and the many inquiries con­ cerning the therapeutic value of ''blue glass in the treatment and cure -8- of cataract cases, a few remarks in favor of this almost extinct color may be of general interest, especially when we recall that this is the 250th anniversary of the introduction of blue glass to the optical trade.	cache/hindsight-3554.pdf	txt/hindsight-3554.txt