The unstoppable slugger playing baseball blind Whether on the field or at Harvard, Joe McCormick wasn’t about to let his sudden loss of vision keep him from competing. ← Related Article Visit The Boston Globe Share on Twitter Share on Facebook Comment on this Scroll to top of page Dina Rudick/Globe Staff Joe McCormick was diagnosed with Leber’s hereditary optic neuropathy, or LHON, a degenerative condition that affects only an estimated 35,000 people worldwide and usually comes on during early adulthood. Dina Rudick/Globe Staff McCormick plays Beep Baseball, an adapted national pastime for the blind and visually impaired. Pictured, Joe, wearing the blindfold that levels the Beep Baseball playing field, drills in Watertown. Dina Rudick/Globe Staff In Beep Baseball, the pitcher and batter are on the same team, and the batter swings based on carefully practiced timing. Dina Rudick/Globe Staff After contact, six fielders on the other team attempt to smother the beeping baseball, and if they grab it before the batter reaches a 4-foot-tall buzzing base 100 feet from the plate, they record the putout. Dina Rudick/Globe Staff If not, the batter scores. One catch: Either first or third base can buzz, depending on the umpire’s whim. Dina Rudick/Globe Staff They say that only five fly balls have been caught in Beep Baseball’s 40-year history, so hitting the ball in the air pretty much guarantees a runner enough time to score. Dina Rudick/Globe Staff The Renegades’ sighted coach, Rob Weissman, at practice in April.