Group 1 ( 50 patients ) was treated 4 times daily with preserved sodium hyaluronate 0.1 % , group 2 ( 50 patients ) was treated 4 times daily with diquafosol 3 % , and group 3 ( 50 patients ) was treated 4 times daily with diquafosol 3 % and preservative-free sodium hyaluronate 0.1 % eye drops for 3 months .