Compliance in glaucoma patients is different from that in patients with most other systemic diseases for which the primary intervention involves either the oral administration of a pill or intravenous administration of a medication. Most individuals know how to take a pill; by contrast, the proper administration of eye-drops may be difficult for many patients. Numerous studies have focused on medication persistency and compliance,1 but few have examined whether the eye-drops that are administered actually get into the eye.2 3 Therefore, we investigated the quality of the topical eye-drop instillation technique in patients diagnosed as having open-angle glaucoma (OAG) or ocular hypertension (OHT) and assessed the relation between the ability to administer eye-drops properly and disease severity. A total of 138 patients with OAG (n = 87) or OHT (n = 51) treated with at least one topical ocular hypotensive medication for a minimum of 1 month were …