Purpose.To assess whether thyroid d isease is indepen-dently associated with open-angle g laucoma (OAG),using history of thyroid disease and curre nt thyroxine use.Methods.The Blue Mountains Eye Stud y examined 3654persons,aged 49-97years.Intervie wers collected self-reported history of diagnosis and treatment for thyroid disease.Eye examinations included applanation tonome-try,stereoscopic optic disc photography and automated perimetry.OAG was diagnosed from th e presence of matching typical glaucomatous field changes and optic disc cupping,independent of intraocula r pressure.Associations between thyroid disease(history and treatment )and OAG were assessed in a multivariate model.Results.Of 324participants(8.9%)reporting history of thyroid disease,147(4.0%)were currently using thyroxine.Although we could not accurately categorize the thyroid disorder for all cases,current use of thyroxine sugg ests a prior hypothyroid state.All thyroid dise ase subgroups affected women more frequently than men,P=0.001.OAG was diagnosed in 108subjects(3.0%)and was more frequent in those reporting past thyroid dise ase(4.6vs2.8%).This relationship was not statistic ally significant after ad-justing for potential confounders,multivariate odds ratio(OR)1.6;95%confidence interval(95%CI 0.9-2.9).OAG was significantly more frequen t,however,in subjects reporting current thyroxine use(6.8vs2.8%),multivariate OR 2.1;95%CI 1.0-4.4,or history of thyroid surgery(6.5vs2.8%),multivariate OR 2.5;95%CI 1.0-6.2.Conclusions.This population-based study suggests that thyroid disease,indicated by current thyroxine use or past thyroid surgery,could be indepen-dently related to OAG. Purpose. Assessment of thyroid d isease is indepen-dently associated with open-angle g laucoma (OAG), using history of thyroid disease and curre nt thyroxine use. Methods. The Blue Mountains Eye Stud y examined 3654persons, aged 49-97 years. Intervie wers collected self-reported history of diagnosis and treatment for thyroid disease. Etness examinations included applanation tonome-try, stereoscopic optic disc photography and automated perimetry. OAG was diagnosed from epresence of matching typical glaucomatous field changes and optic disc cupping, independent Of intraocula r pressure. Associations between thyroid disease (history and treatment) and OAG were assessed in a multivariate model. Results. Of 324 participants (8.9%) reporting history of thyroid disease, 147 (4.0%) were currently using thyroxine. Although we could not-mentioned categorize the thyroid disorder for all cases, current use of thyroxine sugg ests a prior hypothyroid state. All thyroid dise ase subgroups affected women more frequentl y than men, P = 0.001.OAG was diagnosed in 108 subjects (3.0%) and was more frequent in those reporting past thyroid disesese (4.6 vs. 2.8%). This relationship was not statistic ally significant after ad-justing for potential confounders 95% confidence interval (95% CI 0.9-2.9). OAG was significantly more frequent, however, in subjects reporting current thyroxine use (6.8 vs. 2.8%), multivariate OR 2.1; 95 % CI 1.0-4.4, or history of thyroid surgery (6.5 vs. 2.8%), multivariate OR 2.5; 95% CI 1.0-6.2. Conclusions. This population-based study suggests that thyroid disease, indicated by current thyroxine use or past thyroid surgery, could be indepen-dently related to OAG.