This is a single center, investigator-blinded (investigator masked), head to head comparison of Restasis® and its vehicle, Refresh® Dry Eye Therapy in 24 patients. Three target fingernails will be identified in each subject. Two of the target nails will be the two nails that have the most severe signs of brittle nail syndrome. The third target nail will be a normal nail or, in the absence of a normal nail, the patient's second-healthiest appearing nail. The patients most normal-appearing nail will be untreated so that growth in the treated nails can be compared to growth in an untreated normal nail, this will be the fourth target nail. Study medication will be applied to target nails (the subjects may also apply to all nails if they wish, except one nail which will be untreated in order to determine the subject's baseline rate of fingernail growth) for 24 weeks. The target nails will be assessed at each visit, every four weeks. There will be a 12-week follow up period after treatment is completed.