Items with this property have Blinding Flash clicky and can generate a flash of light that has a chance to blind opponents. Saving throw DC (fortitude) of this effect is so low, you may find this effect rather useless in high level adventures.
This stub is related to Dungeons and Dragons Online and needs to be filled out. If you are considering filling it out, some good places to check would be both the google and ddo.com forum search pages. You can help expand it by clicking at the top of the page.