Does lacrimal duct occlusion decrease intraocular pressure in patients refractory to medical treatment for glaucoma? A randomized, sham-controlled, crossover trial.

We temporarily occluded lacrimal ducts with dissolvable collagen inserts in a randomized, double masked, sham-controlled crossover trial to test whether longer ocular contact of eye drops lowers intraocular pressure in patients with refractory glaucoma. Patients were randomized to the sequence temporary lacrimal duct occlusion----21 day washout----sham occlusion (6 patients), or the reverse order (5 patients); all maintained their usual medication. Compliance was greater than 90% for every patient as assessed by medication diaries kept by each patient's medication partner. There was no treatment effect (bivariate Wilcoxon chi 2 = 0.10, p = 0.95) or treatment-period interaction (chi 2 = 2.87, p = 0.24). However, whichever treatment was received first significantly lowered intraocular pressure (left eye first period X:[ipr50] = 3.0: [-6.0, -1.0] mmHg, right eye = -3.0:[-6.0, -1.0] mmHg, bivariate response chi 2 = 5.92, p = 0.05). Although lacrimal duct occlusion appears to have no clinical benefit, more careful supervision of eye drop administration may be efficacious for treating some patients with medically refractory glaucoma.