Patients received a single dose of either unpreserved trehalose 30 mg/mL and sodium hyaluronate 1.5 mg/mL ( TH-SH , Thealoz Duo ) , unpreserved sodium hyaluronate , 0.15 % ( HA , Hyabak ) or sodium chloride , 0.9 % ( NaCl , Hydrabak ) eye drops .