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August 08, 2011
Visual acuity tests demonstrate that big leaguers and Olympic softball players simply see better than the rest of us
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August 08, 2011

Major League Vision

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Visual acuity tests demonstrate that big leaguers and Olympic softball players simply see better than the rest of us

A major league player may not have faster raw reaction times than you do, but he probably has better vision.

Because hitting hinges on anticipation, anything that gives a player an early clue as to where and how fast the ball will go should give him a better chance of intercepting it with his bat. That might be pitch count, which narrows the likely pitches to come (batters fare much better on 3-and-1 than on 0-and-2 pitches); the orientation of fielders; or the position of the catcher. It might also be information derived from the ball itself, such as its "flicker"—the indication of spin direction produced by the rotating seams. The earlier he or she can pick up such cues, the better his or her chance of connecting.

Between 1992 and '95 a group of ophthalmologists and other specialists tested the vision of 387 players in the Dodgers' organization. The first year the doctors used a commercially available visual acuity test that showed players Landolt rings—circles with a gap in one section that the viewer must pick out. This test gauged vision only up to 20--15, which means that the viewer can see something from 20 feet away that the average person would have to be within 15 feet to see. To the doctors' amazement, 81% of the pro players maxed out the test. "The next year we had to use different images," says Daniel M. Laby, an ophthalmologist who works with the Red Sox in spring training. "From 1993 on, our test went down to 20--8." That is the theoretical limit of human vision, given the morphology of rods and cones, the two types of photoreceptors in the human eye.

With the recalibrated test, the average visual acuity of pro baseball players was found to be about 20--13, and only a small number of players, usually pitchers, were worse than 20--20. About 2% of players achieved results better than 20--9, approaching the theoretical limit. "I can pretty comfortably say that in 20 years of caring for peoples' eyes, I've never seen someone outside pro athletics achieve that," Laby says. A study of U.S. Olympic athletes published in May found similar results among elite softball players, whose average visual acuity was approximately 20--11. The baseball players studied were also superior to the overall population—and big leaguers were better than minor leaguers—on an array of other tests, such as picking out figures that only slightly contrast with the background and perceiving fine variations in depth.

Many players seek to enhance their contrast sensitivity, at least in the field, with tinted sunglasses that help them pick out a white ball against white clouds, just as skiers wear tinted goggles that make the relief of a white hill jump out. Mark McGwire used custom-tinted contact lenses at the plate, though it's not clear how much they might have added to his 20--10 corrected vision.

Given the importance of picking up contrast and other visual cues, it could be that the seams of a professional softball—red on yellow as opposed to the red on white of a baseball—help explain why baseball players can't hit softball pitchers, and why even softball batters rarely hit the best softball pitchers.