Objective To evaluate the efficacy and safety of two different concentrations of cyclosporine A (CsA) in aqueous solution compared to vehicle in patients with dry eye syndrome.

Design Multicentre, randomised, double-masked, vehicle-controlled, clinical trial.

Methods A total of 183 patients were enrolled and randomised to either CsA 1% (group A), CsA 0.05% (group B) or vehicle only (group C). The main objective was to evaluate the efficacy of CsA aqueous solution in the reduction of signs and symptoms in patients with moderate to severe dry eye disease.

Results An early (day 21) statistically significant improvement (p<0.05) was evident in four symptoms and three ocular signs in group A. An equivalent improvement in three symptoms and three ocular signs was demonstrated in group B. A significant improvement was identified in two symptoms and two ocular signs in group C. Comparing the three groups together, group A performed better in four symptoms than group B did with just one symptom. Group C did not show significant improvement. At day 42, group A showed improvement in four symptoms, while group B showed improvement in one symptom and one ocular sign.

Conclusions Cyclosporine A reduced complaints and improved major ocular signs in patients with moderate-to-severe dry eye disease. The group treated with the 0.1% cyclosporine A aqueous solution outperformed the other groups.