Tear volume estimation using a modified Schirmer test: a randomized, multicenter, double-blind trial comparing 3% diquafosol ophthalmic solution and artificial tears in dry eye patients

PURPOSE We aimed to evaluate the feasibility of using a modified Schirmer test to determine the increase in tear volume after administration of 3% diquafosol ophthalmic solution (diquafosol 3%) in dry eye patients. PATIENTS AND METHODS A randomized, multicenter, prospective, double-blind clinical study recruited 50 qualified subjects. They received diquafosol 3% in one eye and artificial tears in the other eye. The study protocol comprised a screening and treatment procedure completed within 1 day. The Schirmer test was performed on closed eyes three times a day. The primary efficacy end points were the second Schirmer test scores 10 minutes after the single dose. Secondary end points were the third Schirmer test scores 3 hours and 40 minutes after the single dose and the symptom scores prior to the second and third Schirmer tests. RESULTS According to the Schirmer test, 10 minutes after administration, diquafosol 3% significantly increased tear volume compared to artificial tears. Diquafosol 3% and artificial tears both showed significant improvements in the symptom scores compared to baseline. However, there was no significant difference in the symptoms score between diquafosol 3% and artificial tears. CONCLUSION The modified Schirmer test can detect a minute change in tear volume in dry eye patients. These findings will be useful in the diagnosis of dry eye, assessment of treatment benefits in daily clinical practice, and the development of possible tear-secreting compounds for dry eye.