EMPLOYEE RECEIVED A CHEMICAL BURN TO HIS RIGHT EYE. HE WAS TREATED WITH PRESCRIPTION MEDICATIONS AND WAS RESTRICTED IN HIS WORK DUTIES. HE WAS CHECKING A VALVE SPOOL FOR A LEAK; THERE WAS A SMALL HOLE CLOSE TO THE UNDERFLOW CONTROL VALVE & LIQUOR/MUD SPRAYED OUT AND GOT INTO HIS EYE.