"Read the Bottom Line"

Though dozens of different eye charts have been proposed by assorted experts in half a century, none has displaced the familiar Snellen chart, topped by its king-sized "E". But this week the American Optometric Association announced the adoption of a chart made up of numerals, which, its members hope, will send the old Snellen into outer darkness.

Dr. J. Ottis White, president of the optometrists,* attacked the Snellen chart as a crude test which ignores the way people actually use their eyes. "The new A.O.A. standard tests visual recognition--meaningful vision--rather than mere visual acuity," said Optometrist White. "It takes into account the many distinct skills involved in visual recognition, including light perception, contrast perception, resolving power, line perception and shape perception." The eyes of ordinary mortals could not detect these fine points; to them, the new chart looked like just a lot of heavily drawn figures.

In the new A.O.A. scale, normal vision gets a plus rating. Plus 1 roughly represents the Snellen's 20/20, zero the Snellen's 20/40 (ability to read at 20 ft. what normal eyes should read at 40 ft.), Minus 1 the Snellen 20/80, and Minus 2 the old 20/160 (which takes extra thick glasses to correct). Plus 2 in the new scale indicates an eagle-eyed ability to read at 20 ft. what most people cannot read beyond 10 ft.

Many eye doctors were inclined to sniff at the optometrists' new chart, arguing that most such gadgets are crude at best, and the Snellen is no cruder than the rest. However, the last word may be the optometrists' : they give three times as many eyesight tests as the ophthalmologists.

*Who are not licensed to treat eye diseases, but simply to measure the eyes' performance.

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