Corneal and retinal effects of ultraviolet-B exposure in a soft contact lens mouse model

PURPOSE. To investigate the lipid and DNA oxidative stress as well as corneal and retinal effects after ultraviolet B (UV-B) exposure in mice, with or without silicon hydrogel soft contact lenses (SCL). METHODS. Twenty-eight C57BL6-strain male mice were divided into four groups: group I, control group with no SCL (SCL [-]) and no UV-B exposure (UV-B [-]); group II, senofilcon A SCL (senofilcon [+]) with UV-B exposure (UV-B [+]); group III, lotrafilcon A SCL (lotrafilcon [+]) with UV-B exposure (UV-B [+]); and group IV, no SCL (SCL [-]), but with UV-B exposure (UV-B [+]). All mice except group I received UV-B exposure for 5 days for a total dose of 2.73 J/cm ². All mice underwent tear hexanoyl-lysine (HEL) and tear cytokine ELISA measurements, and fluorescein and rose bengal corneal staining before and after UV-B exposure. Corneal specimens underwent immunohistochemistry staining with CD45, HEL, 4-hydroxynonenal (4-HNE), and 8-hydroxy-20-deoxyguanosine (8-OHdG) antibodies and evaluation with electron microscopy. RESULTS. All mice without SCL but exposed to UV-B developed corneal edema, ulcers, or epithelial damage compared with mice with senofilcon A SCL and exposure to UV-B. Tear HEL and cytokine levels significantly increased in mice without SCL after UV-B exposure. Immunohistochemistry showed a significantly higher number of cells positively stained for CD45, 8-OHdG, HEL, and 4-HNE in the corneas of mice without SCLs compared with those with senofilcon A after UV-B exposure. CONCLUSION. Silicon hydrogel SCL showed corneal and retinal protective effects, owing to UV blocking properties, against oxidative stress-related membrane lipid and cellular DNA damage.