Prevalence of Open-Angle Glaucoma in Greece: The Thessaloniki Eye Study FOTIS TOPOUZIS, M. ROY WILSON, ALON HARRIS, ELEFTHERIOS ANASTASOPOULOS, FEI YU, LEONIDAS MAVROUDIS, THEOFANIS PAPPAS, ARCHIMIDIS KOSKOSAS, AND ANNE L. COLEMAN ● PURPOSE: To estimate the prevalence of open-angle glaucoma (OAG) in a population-based sample of sub- jects 60 years of age or older in Thessaloniki, Greece. ● DESIGN: Cross-sectional population-based study. ● METHODS: Subjects randomly identified from munici- pality registers in Thessaloniki underwent a complete ophthalmologic examination. Glaucoma was defined in two ways. Definition 1 was based on the presence of both glaucomatous optic disk and confirmed glaucomatous visual field defect. Subjects also were classified as having glaucoma when the clinical judgment was strongly in favor of the presence of glaucoma even though the strict criteria were not fulfilled (definition 2). ● RESULTS: Of the 3,617 eligible subjects, 2,554 (71%) participated. The prevalence of OAG was 3.8% and 5.5% by definitions 1 and 2, respectively. The prevalence of primary OAG was 2.7% and 3.8% by definitions 1 and 2, respectively, and the prevalence of pseudoexfoliation glaucoma (PEXG) was 1.1% and 1.7% by definitions 1 and 2, respectively. Pseudoexfoliation was present in 11.9% of participants, whereas 15.2% among those with pseudoexfoliation had PEXG. ● CONCLUSIONS: The prevalence of OAG in the Thes- saloniki Eye Study (TES) is similar or slightly higher compared with other population-based studies in White persons. The overall slightly higher prevalence of OAG in the TES compared with other studies may be attrib- uted to the high prevalence of PEXG in the TES. (Am J Ophthalmol 2007;144:511–519. © 2007 by Elsevier Inc. All rights reserved.) G LAUCOMA IS A MAJOR GLOBAL HEALTH PROBLEM. Glaucoma of all types is the second leading cause of blindness worldwide, with approximately 6.7 million people being blind as a result of the disease. 1 The most commonly occurring type of glaucoma is primary open-angle glaucoma (POAG), 2,3 whereas one of the more common types of secondary open-angle glaucoma (OAG) is pseudoexfoliation glaucoma (PEXG). 4 The prevalence of glaucoma differs among specific ethnic groups. 3,5,6 Ethnic-specific differences in glaucoma prevalence and risk factors may provide clues to the pathogenesis of glaucoma. Population-based studies have documented the prevalence of OAG in many populations throughout Northern Europe, Asia, Australia, and North and Central America. 3,7–19 However, few studies have focused on Southern European populations. 20 –22 Addition- ally, although the prevalence of OAG has been reported in numerous studies worldwide, most of these studies did not assess pseudoexfoliation. 23,24 We performed a MEDLINE search using pseudoexfoliation glaucoma, exfoliation glaucoma, glaucoma prevalence, and population-based studies as key- words and found only one large population-based glaucoma study that specifically investigated PEXG prevalence in White persons 25 and two additional studies of the popula- tion of India. 18,26,27 The Thessaloniki Eye Study (TES) was designed to estimate the prevalence of POAG and PEXG in a well-defined population in Thessaloniki, Greece. METHODS THE TES IS A CROSS-SECTIONAL, POPULATION-BASED, EPI- demiologic study of chronic eye diseases in the Greek population of Thessaloniki. Thessaloniki is the major urban center in Northern Greece and is the second largest city in Greece, after Athens. This urban area has a stable and homogenous population, with 97.7% of the popula- tion identified as being of Greek ethnicity. According to the National Statistical Service of Greece, it is considered representative of the general population in Greece. 28 The initial recruitment frame of the TES consisted of 5,000 people, 60 years of age or older, who were identified randomly in February 1999 from approximately 321,000 persons registered in the municipality registers of the city of Thessaloniki. Subject recruitment is described in detail elsewhere. 29 In summary, randomization was provided by the municipality statistical service. A certificate of regis- tration in the municipality registers is obligatory and is required by the Thessaloniki Police Department for issu- ance of a Greek citizen photo identification card. A similar certificate is required by Greek authorities for obtaining a Accepted for publication Jun 19, 2007. From the II Department of Ophthalmology, Aristotle University of Thessaloniki, Thessaloniki, Greece (F.T., E.A., L.M., T.P., A.K.); School of Medicine, University of Colorado at Denver and Health Sciences Center, Denver, Colorado (M.R.W.); Department of Ophthalmology, Indiana University, Indianapolis, Indiana (A.H.); and Center for Eye Epidemiology, Jules Stein Eye Institute, David Geffen School of Medi- cine, University of California Los Angeles, Los Angeles, California (F.Y., A.L.C.). Inquiries to Fotis Topouzis, Aristotle University of Thessaloniki, II Department of Ophthalmology, General Hospital “Papageorgiou,” Perife- riaki Odos Thessalonikis, N. Efkarpia 56403, Thessaloniki, Greece; e-mail: ftopouzis@otenet.gr © 2007 BY ELSEVIER INC.ALL RIGHTS RESERVED. 0002-9394/07/$32.00 511 doi:10.1016/j.ajo.2007.06.029