Skip to main content

Eye on the ball: IU scientists explore vision and performance in baseball

Indiana University optometry researchers partner with IU baseball team to investigate impact of ‘vision training’ on sports performance

Apr 25, 2019

A great baseball team requires a coach with the vision to win. It also requires players with the vision to literally see the ball as it flies over the plate at speeds that regularly reach up to 90 mph.

This simple fact has spawned a small industry over the past several decades that purports to improve batting performance by teaching players to see more clearly, track the ball more accurately and improve their hand-eye coordination. Yet the effectiveness of these methods has remained largely untested by rigorous scientific methods.

In response, Indiana University researchers at the IU School of Optometry, in collaboration with the Duke Institute of Brain Sciences, launched a collaboration last year to study vision training in baseball.

Description of the following video:

[Video: A baseball player practices hitting in a batting cage.]

[Words appear: Indiana University presents]

Nicholas Port speaks in voiceover: Vision training has been around in the field of optometry for many, many years.

[Video: A different baseball player hits a ball in the batting cage.]

[Video: Port is shown sitting in the batting cages room addressing someone off screen]

[Words appear: Nicholas Port, Associate professor, IU School of Optometry]

Port speaks: And in the last 20 years people have wondered whether they could use some of those exercises or develop new exercises that might improve athletic performance.

[Video: Port is looking at a monitor that shows a simulation of a ball being hit on a baseball field after the baseball player hits in the batting cage.]

[Video: A baseball player is doing a vision test on a small monitor.]

[Video: Lyndsey Ferris is shown sitting in the batting cages room addressing someone off screen]

[Words appear: Lyndsey Ferris, Ph.D. student, IU School of Optometry]

Ferris speaks: We’re looking to see if sports vision training, specifically by some of these newer digital-based models, can produce sports-specific performance gains in players.

[Video: An IU baseball player is walking out on the field before a game. A row of players are high-fiving him as he walks by.]

Ferris speaks in voiceover: We’re focusing on the men’s baseball team.

[Video: An IU baseball player walks past a line of fellow players, tapping baseball mitts as he walks along.]

[Video: Jeff Mercer is shown sitting in a locker room addressing someone off screen]

[Words appear: Jeff Mercer, Head coach, IU baseball]

Mercer speaks: When someone talks about the ability to potentially help and improve your vision and …

[Video: IU baseball players hit balls pitched to them during a game.]

Mercer speaks in voiceover:  … the ability to recognize more quickly and hopefully increase your hand-eye coordination because you’re able to see better …

[Video: A baseball player runs to a base. He taps his helmet with other players.]

Mercer speaks in voiceover: … It was a no-brainer for us, and we were excited to at least give it a shot.

Port speaks: We’re focusing a lot on the tools by a company called Synaptic.

[Video: Port places a ball on a batting tee. A player wearing vision goggles hits the ball.]

Port speaks in voiceover: And they have a range of products that they have been creating to train athletes. This includes strobe glasses …

[Video: A player uses a mobile device connected to a monitor to do a vision test.]

Port speaks in voiceover: … some tablet apps that have you do some visual skills …

[Video: A player stands behind a light rail and moves his eyes with the motion of the light along the rail. The player presses a remote next to the light rail.]

Port speaks in voiceover: … and then they have a light rail, which simulates a ball moving down at an angle.

Ferris speaks in voiceover: You’ll hear stores from players that will swear their vision training activity really made the difference to get them to that next level of performance …

[Video: A player puts on vision goggles and then gets ready to bat in the batting cages.]

Ferris speaks in voiceover: … but we don’t have a lot of hard, scientific evidence to back that up.

[Video: Ferris takes notes during a vision training exercise. A player is doing a vision test on a small monitor. Ferris speaks to players before a vision exam.]

Ferris speaks in voiceover: And that’s where this study is really exciting, because we’re taking the systems that are commercially available, and we’re testing them to determine do they really provide these gains.

[Video: Mercer appears on screen]

Mercer speaks: Being at a university that has the capabilities and the research opportunities that we have here is a tremendous advantage …

[Video: IU baseball players hits balls pitched to them during a game.]

Mercer speaks in voiceover: … in the technology investment into the athletes across the board. And it allows our athletes to really develop and grow much more rapidly.

[Video: IU baseball player runs to home base. Other players are waiting there cheering and jumping in celebration after the home run.]

[Screen fades to black]


[Words appear: Fulfilling the promise


IU researchers discuss their collaboration with the IU baseball team

The players in the study are members of the IU baseball team under head coach Jeff Mercer. The lead researcher on the project at IU is Nicholas Port, an associate professor at the IU School of Optometry.

“You’re trying hit a round ball with a round stick – when that ball is traveling at 70 to 90 miles per hour at a distance of 60 feet – so, presumably, vision is important in baseball,” Port said. “What we decided to do was design a study to see whether, in a systematic and scientific way, we could measure the effects of vision training on baseball performance.”

To conduct the study, Port recruited players from the IU baseball team to participate in 30-minute exercises at least three times per week for nine weeks. Lyndsey Ferris, a Ph.D. student at the IU School of Optometry, also joined the project to lead data collection.

Media kit: Download additional images and video clips

“We really tried to tailor our tests to the players’ strengths and weaknesses, so they were constantly challenged to get to that next level of improvement,” said Ferris, who is also a member of the Air Force. “The general feedback from the players has been very positive; they oftentimes ask to get another round of a particular activity.”

These tests include three main exercises:

  • The use of a “light rail,” in which players are asked to press a button at a specific moment as a small LED light travels down a long track. This test is designed to simulate the eye movement required to trace a baseball in flight.
  • A tablet-based test to gauge players’ ability to quickly discriminate between different targets and act in a specific way upon certain targets.
  • “Strobe glasses,” in which players’ vision is completely blocked 10 to 90 percent of time as they swing a bat at a ball in flight.
Nicholas Port and Lyndsey Ferris review information on a player's swing
Nicholas Port, left, and Lyndsey Ferris review information on a player’s swing.Photo by Kevin Fryling, Indiana University

The players also participated in a week of baseline tests before the main study. They took up to 500 swings to gauge their starting batting consistency and performance. For the parts of the study involving swinging a bat, the players’ form was recorded by cameras that captured the physics of each motion.

These tests were conducted at the Dr. Lawrence D. Rink Center for Sports Medicine and Technology, which is the recently constructed facility at the south end zone of IU’s Memorial Stadium, and the batting cages in the baseball complex at Bart Kaufman Field.

As a first baseman at Wright State University, where he also served as head coach before joining IU in 2018, Mercer is familiar with the challenge of striking a moving object in flight. He said the ability to make out the smallest details, such as the placement of the hand on the ball as it leaves the pitcher’s grip or the spin of the ball as it proceeds over the plate, can provide players with critical information in the heat of the moment.

IU baseball player Patrick Loeffler wears strobe glasses during batting practice
IU baseball player Patrick Loeffler wears “strobe glasses” during batting practice.Photo by Kevin Fryling, Indiana University

“Being an offensive player myself in my career, I understand the importance of vision,” he added. “So, when someone came up to me to talk about potentially helping improve (our players’) vision and their ability to recognize moving objects more quickly, and hopefully increase their hand-eye-coordination … it was a no-brainer. Being at a university with the capabilities and the research opportunities (of IU), it’s a tremendous advantage.”

Port and Ferris plan to conduct a second round of data collection in the fall, after the whirlwind of the college baseball season is over. They also plan to enroll women from the IU softball team in the study’s second phase.

Port’s collaborator and the lead researcher on this study is Greg Appelbaum, an associate professor of psychiatry and behavioral sciences at the Duke University School of Medicine. The research is supported by a grant from the U.S. Army Research Office.


IU Newsroom

Kevin Fryling

Senior storyteller

More stories