VSP Global has acquired a stake in RightEye, a company specializing in the use of eye-tracking technology to improve patient care and vision performance. The size of the investment has not been disclosed. RightEye's customers include hospitals, the U.S. military, Major League Baseball (MLB) and more than 100 independent optometrists across the U.S. The RightEye technology is currently used by around 50 VSP network doctors in their practices. As part of the deal, VSP Global now has a seat on RightEye's board of directors. RightEye's vision tests require users to sit and follow graphics on a screen in a playful manner, such as by tracking a dot around a circle or identifying and blowing up aliens invading Planet Earth. RightEye's cloud-based software then interprets the interactions and generates an instant report, complete with information on visual processing, visual speed and accuracy, depth perception, dry eye symptoms and more.