Elsevier

Ophthalmology

Volume 119, Issue 6, June 2012, Pages 1134-1142
Ophthalmology

Original article
Prevalence of Primary Angle Closure and Primary Angle-Closure Glaucoma in a Southwestern Rural Population of Japan: The Kumejima Study

Presented in part as a poster at: American Academy of Ophthalmology Annual Meeting, November 2008, Atlanta, Georgia.
https://doi.org/10.1016/j.ophtha.2011.12.038Get rights and content

Purpose

To determine the prevalence and ocular biometry of primary angle closure (PAC) and primary angle-closure glaucoma (PACG) in a rural population in southwestern Japan.

Design

Population-based cross-sectional study.

Participants

All residents aged 40 years or older in Kumejima, Okinawa, Japan.

Intervention

Of the 4632 residents 40 years of age or older, 3762 (participation rate, 81.2%) underwent a detailed ocular examination, including measurement of the best-corrected visual acuity, slit-lamp examination, Goldmann applanation tonometry, static and dynamic gonioscopy, undilated stereoscopic optic fundus photographs, autorefractometry, partial coherence laser interferometry, noncontact specular microscopy, and screening visual field (VF) testing using frequency-doubling technology. If glaucoma or related or other ocular disorders were suspected, the subject was referred for a definitive examination including VF testing with the 24–2 Swedish Interactive Thresholding Algorithm Standard program of the Humphrey Field Analyzer (Carl Zeiss Meditec, Dublin, CA).

Main Outcome Measures

Prevalence rates of primary angle-closure suspects (PACS), PAC, PACG, and PACG suspects.

Results

Under the standard definitions of the International Society of Geographical and Epidemiological Ophthalmology, the prevalence rates of PACS, PAC, and PACG were 8.8%, 3.7%, and 2.0%. Extending the diagnosis of PAC and PACG to include people with narrow but open angles and primary peripheral anterior synechiae, the prevalence rates of PAC and PACG increased to 6.0% and 2.2%, respectively. Hence, broadening the diagnostic categories in PAC and PACG increased the prevalence rates by 62% and 10%. Twenty-three subjects (0.6%; 95% confidence interval, 0.4%–0.9%) had a history of or were diagnosed with acute PAC. Older age, female gender, hyperopic refractive error, short axial length, and shallow anterior chamber depth were independent predictors of an occludable angle.

Conclusions

The prevalence of PACG in Kumejima (2.2%) was one of the highest reported in population-based studies, that is, 3.7 times higher than in the Tajimi Study carried out in an urban center located in the central area of the main island of Japan.

Financial Disclosure(s)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Section snippets

Study Population

The Kumejima Study was a population-based epidemiologic survey of ocular diseases, especially of glaucoma, among all residents 40 years of age or older in Kumejima, Okinawa Prefecture, Japan. Kumejima is an island in southwestern Japan. This study was conducted from May 2005 through August 2006. The investigation followed the tenets of the Declaration of Helsinki and the municipal law of Kumejima Town for protecting private information. The ethics committee of Kumejima Town approved the study

Population, Participants, and Participant Rate

The number of registered residents 40 years of age or older in Kumejima was 5289, but 657 were identified as nonresidents or deceased or had relocated during the screening period. Of the remaining 4632 eligible residents, 3762 (participant rate, 81.2%) completed a screening examination in the Public Kumejima Hospital (3572 subjects) or in their own or nursing homes (190 subjects). Of the 3762 participants, 1363 were not referred for a definitive examination, but the rest (2399; 64.0%) were

Discussion

Kumejima is an island in Okinawa Prefecture in southwestern Japan. The composition of the population in Kumejima is almost identical to that of Okinawa Prefecture.18 Therefore, Kumejima was chosen for the current population-based survey because the Kumejima population is thought to represent better the population of Okinawa Prefecture. Moreover, the percentage of Kumejima residents who relocated from or to other islands or other areas in Japan was relatively low compared with residents of the

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    Manuscript no. 2011-303.

    Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

    Supported by a Grant-in-Aid for Scientific Research by the Ministry of Health, Labour and Welfare, Tokyo, Japan (H18-Sensory-General-001); the Grant-in-Aid for Scientific Research (C) 17591845 from the Ministry of Education, Culture, Sports, Science and Technology, Tokyo, Japan; and a fund from the Japan National Society for the Prevention of Blindness, Tokyo, Japan.

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