WASHINGTON—Rep. Dan Crenshaw (R-Texas), a former Navy SEAL who lost his right eye in an explosion in Afghanistan, said on Saturday he will take a month-long leave of absence from Congress after emergency surgery for a detaching retina in his other eye. “The surgery went well, but I will be effectively blind for about a month,” the Texas Republican wrote in a statement on Twitter. He said his congressional offices will remain open but apologized to constituents for being “pretty much off the grid for the next few weeks.” Crenshaw, 37, a former Navy lieutenant commander who served in Afghanistan and Iraq, said the retina in his left eye appeared to be detaching as a result of extensive damage suffered in a 2012 attack in Afghanistan’s Helmand Province. “Anyone who knows the history of my injuries knows that I don’t have a ‘good eye,’ but half a good eye,” Crenshaw …