This one-year study evaluates the long-term safety and effectiveness of bimatoprost solution application to the eyelid margin (where the eyelashes meet the skin) to treat hypotrichosis of the eyelashes (inadequate or not enough eyelashes). There will be two different types of subjects participating in the study 1)those with inadequate eyelashes due to natural causes or 2) those with inadequate eyelashes following a complete course of chemotherapy treatment. There will be two treatment periods of six months each. Subjects will receive either the study medication or vehicle in either of the two treatment periods.