Prevalence of angle-closure disease in a Korean population: The Namil Study Report 2 EVIDENCE LEVEL III CONFIRMATORY Joo Hwa Lee 1 , Yong Yeon Kim 2 and The Korean Glaucoma Society Department of Ophthalmology, Inje University Sanggye Paik Hospital1, Korea University College of Medicine 2, Seoul, Korea. DISCUSSION PURPOSE This study was performed to estimate the prevalence of primary angle-closure suspect (PACS), primary angle-closure (PAC), and primary angle-closure glaucoma (PACG) in a Korean population as a part of the Namil Study. <Definitions of angle closure disease> Definition Characteistics Primary angle-closure suspect (PACS) posterior trabecular meshwork not visible by gonioscopy in ≥ 3 quarters of the angle circumference Primary angle closure (PAC) PACS plus elevated IOP, peripheral anterior synechiae, iris distortion, and/or glaukomflecken Primary angle-closure glaucoma (PACG) PAC plus optic nerve/visual field damage Population (year) Prevalence Myanmar > 40 yrs (2007) 2.5% China > 50 yrs (2006) 1.5% Mongolia > 40 yrs (1996) 1.4%  Singapore (Chinese) > 40yrs (2000) 1.0% Thailand > 50 yrs (2003) 0.9% India > 40 yrs (2000) 1.08% India > 40 yrs (2008) 0.88% Japan > 40 yrs (2005) 0.6% Japan > 40 yrs (1991) 0.34% Korea (Namil Study) > 40 yrs 0.65% INTRODUCTION Glaucoma is one of the common causes of world blindness, and the majo-ity of those blinded reside in Asia. It has become recognized that angle-closure glaucoma is more common in people of Asian origin than those with European or African ethnicity. Prevalence of primary angle-closure glaucoma (PACG) varies according to the study populations. The published prevalence rates of PACG are highest for the Eskimo popul-ation and lowest for the white population. In between these come the Mong-ol, Chinese, Indian, Thai, and Japanese populations. However, there has been a paucity of population-based epidemiological study of PACG in Korea. RESULTS Gender Total Male (total = 643) Female (total = 889) PACS 8 21 29 PAC 1 6 7 PACG 4 10 Table 4. Prevalence of PACG in Asians PATIENTS AND METHODS The representatives of rural Korean population in Namil-myon, Chung-cheongnamdo were selected in this population-based epidemiologic study. This study included 1,532 people (80.3% participation rate) of 1909 eligible residents aged 40 years or older. Each subject underwent full screening tests for the detection of glaucoma including an interview, Goldmann applanation tonometry, slit-lamp biomicroscopy, refraction, a van Herick test, fundus photography, corneal thickness measurement with ultrasound pachymetry, a visual field test using frequency-doubling technology, gonioscopy, and ocular biometry using IOL master. If the findings were suspicious or equivocal, visual field tests with Humphrey field analyzer as well as optical coherence tomography and scanning laser polarimetry were performed for confirmation of the diagnosis. * Indications of additional examinations (1) FDT VF abnormality - any abnormal area,1% in FDT VF - poor reliability with repeated FDT examinations (2) GAT > 21 mmHg (3) Optic disc abnormality - Cup/disc (C/D) ratio > 0.6 or C/D difference > 0.2 between the 2 eyes - Against the ISN’T rule - Disc hemorrhage or retinal nerve fiber layer defect Population (year) Prevalence Mongolia > 40 yrs (1996) PACS: 6.4% / PACG: 1.4% India – APEDS > 40 yrs (2000) PACS 2.21% / PACG 1.08% India – Chennai Glaucoma Study > 40 yrs (2008) PACS: 7.24% / PAC: 2.75% / PACG: 0.88% Japan - Tajimi Study > 40 yrs (2005) PAC: 0.5% / PACG: 0.6% Korea – Namil Study > 40 yrs PACS: 1.89% / PAC: 0.46% / PACG: 0.65% Table 1. Distribution of primary angle-closure disease (PACS + PAC + PACG) by gender   Age (years) Total 40-49 50-59 60-69 70-79 80- PACS 11 12 7 29 PAC 1 3 2 PACG 10 Table 5. Prevalence of angle-closure disease in Asians CONCLUSION Prevalence of PACG in this population was 0.65%. Primary angle-closure disease was associated with female gender, older age, shallower anterior chamber depth, shorter axial length, and hyperopia. Table 2. Distribution of primary angle-closure disease (PACS + PAC + PACG) by age Normal Angle-closure disease P value Central ACD (mm) 3.07 ± 0.41 2.47 ± 0.33 0.000 AL (mm) 23.32 ± 1.01 22.64 ± 0.68 SE (diopter) 0.19 ± 1.65 0.66 ± 1.33 0.020 IOP (mmHg) 13.48 ± 4.22 13.92 ± 3.20 0.476 Corneal thickness (㎛) 530.08 ± 32.37 529.86 ± 32.66 0.965 REFERENCES Dandona L, Dandona R, Mandal P, et al. Angle-closure glaucoma in an urban population in southern India: the Andhra Pradesh Eye Disease Study. Ophthalmology 2000;107:1710–6 Bourne RR, Sukudom P, Foster PJ, et al. Prevalence of glaucoma in Thailand: a population based survey in Rom Klao district, Bangkok. Br J Ophthalmol 2003;87:1069 –74. Yamamoto T, Iwase A, Araie M, et al. The Tajimi Study report 2. Prevalence of primary angle closure and secondary glaucoma in a Japanese population. Ophthalmology 2005;112:1661–9. Table 3. Comparison of ocular parameters: normal vs primary angle-closure disease (PACS + PAC + PACG) (ACD = anterior chamber depth; AL = axial length; SE = spherical equivalent; IOP = intraocul-ar pressure)