Immortalized Human Corneal Epithelial Cells (HCECs) were cultured in vitro. Cells were observed under phase-contrast microscope and the integrity of cells monolayer was determined by transepithelia electrical resistance (TEER). A permeability of Diethyldithiocarbamate (DDC) through a HCECs monolayer was compared with that of DDC through an excised rabbit cornea. The permeability coefficients of DDC through a HCECs monolayer and a excised rabbit cornea were (29.5?4.8)?10-6cm?s-1 and (34.7?5.2)?10-6 cm?s-1 respectively. The result demonstrates that the permeability of DDC through in vitro cornea may be predicted using HCECs monolayer. In vivo trans-corneal transit of DDC from DSF eye drops was performed. Eye drops with HPMC has 2.8-fold greater for area under the curve (AUC) than eye drops without HPMC, which was attributed to the complex formation of DSF/HPβCD inclusion with HPMC. The lenses opacity was monitored using a slit lamp and results show DSF eye drops can effectively prevent the cataracts development.