Effects of phytoestrogen supplementation in postmenopausal women with dry eye syndrome: a randomized clinical trial

Objective: To evaluate the correlation between tear osmolarity and blood levels of 17-beta estradiol, estrone, and testosterone in postmenopausal women with dry eye syndrome, and to assess the efficacy and safety of oral supplementation with phytoestrogens, lipoic acid, and eicosapentaenoic acid in this population. Design: Cross-sectional study including 66 postmenopausal women with dry eye syndrome. Methods: Sixty-six postmenopausal women with dry eye syndrome were enrolled in a randomized, double-blind, placebo-controlled, crossover study. Patients were divided into 2 groups (groups A and B) and treated, respectively, with phytoestrogen (Bioos, Montegiorgio, Italy) tablets or placebo tablets for 30 days. The 2 treatment periods were separated by a 30-day washout. Patients were examined on days 0 and 30 of each period. Assessments included blood levels of sex hormones, the Schirmer test for tear production, and measurement of tear osmolarity and tear film break-up time. Results: At baseline, all patients had low sex hormone levels, which were correlated with high tear film osmolarity values (r = -0.59, -0.61, -0.58, respectively). After 30 days of therapy, the group treated with Lacrisek (Bioos) had significantly decreased tear osmolarity (P < 0.005) and significantly increased tear production evaluated with the Schirmer test and tear film break-up time values (P < 0.001) compared with the placebo-treated group. Conclusions: Our study confirms that steroid hormones play an important role in ocular surface equilibrium and functions. Consequently, reduced blood levels of these hormones can produce changes at the ocular surface. Phytoestrogen supplementation can significantly improve the signs and symptoms of dry eye syndrome in postmenopausal women.