The Ocular Hypertension Treatment Study has shown that medical treatment of ocular hypertension (OHT) reduces the incidence of primary open-angle glaucoma (POAG) at 5 years by more than 50%.1 The greatest absolute reduction in incidence occurs among those at highest risk based on baseline age, intraocular pressure, central corneal thickness, vertical cup-disc ratio, and pattern standard deviation. In clinical practice, most patients with OHT are followed up for longer than 5 years.1-3 To help clinicians and patients make decisions about the benefit of early medical treatment and the frequency of examinations, we have calculated the 10-year incidence of POAG under 2 scenarios: treated, ie, medical treatment for 10 years, and untreated, ie, no medical treatment for 10 years.