Elsevier

Ophthalmology

Volume 107, Issue 5, May 2000, Pages 998-1003
Ophthalmology

Original Articles
Epidemiology of angle-closure glaucoma: Prevalence, clinical types, and association with peripheral anterior chamber depth in the Egna-Neumarkt glaucoma study

https://doi.org/10.1016/S0161-6420(00)00022-1Get rights and content

Abstract

Objective

To assess the prevalence of primary angle-closure glaucoma (PACG), the frequency of its different clinical presentations, and its association with peripheral anterior chamber depth in a defined population in Northern Italy.

Design

Cross-sectional epidemiologic study in a defined population.

Participants

All subjects resident in the Egna-Neumarkt area of the South Tyrol Region (Northern Italy) and more than 40 years of age were invited to undergo an ophthalmologic examination.

Intervention

After the screening examination, subjects with suspected glaucoma were re-examined at the screening center to confirm the diagnosis. All cases that still proved suspect after the second examination underwent a third phase of investigations and were classified as healthy or as definitely glaucomatous. Each subject was examined according to a standard protocol, including medical history interview, refraction and visual acuity determination, ocular biomicroscopy, evaluation of peripheral anterior chamber depth by means of the Van Herick method, applanation tonometry, optic disc evaluation, and computerized perimetry. Gonioscopy was not performed during initial screening but only in all selected patients in the second and third phases of investigations. The diagnosis of PACG was made on the basis of the concomitant presence of at least two of the following criteria: intraocular pressure ≥ 22 mmHg, glaucomatous optic disc abnormalities, glaucomatous visual field defects. In addition, biomicroscopic or gonioscopic evidence of angle closure was also necessary.

Main outcome measures

Percentage distribution of peripheral anterior chamber depths, prevalence of angle-closure glaucoma, and frequency of the different PACG clinical presentations.

Results

Four thousand two hundred ninety-seven subjects were examined (73.9% overall participation rate). The peripheral depth of the anterior chamber according to the Van Herick method was grade 2 in 14.7%, grade 1 in 2.5%, and grade 0 in 0.3% of the population. The overall prevalence of angle-closure glaucoma was 0.6% (26 cases). Five of these were cases of previous acute attacks resolved by therapy, three were cases of chronic angle-closure after acute attacks, three were intermittent angle-closure glaucomas, and 15 were chronic angle-closure cases.

Conclusions

Occludable angles were more frequent than in other white populations previously studied. The prevalence of PACG is not as low as is usually believed; this type of glaucoma accounts for more than a quarter of all glaucomas found in the Egna-Neumarkt population. The most frequent clinical presentation is chronic angle-closure glaucoma.

Section snippets

Patients and methods

The entire population 40 years of age or older of the Egna-Neumarkt area in the South Tyrol Region, including 11 rural districts, was screened. The study was conducted in the town of Egna-Neumarkt at a specially equipped screening center by appropriately trained ophthalmologists.

The study was composed of three phases. At the first screening visit a specially designed questionnaire was administered along with an ophthalmologic examination consisting of the following tests:

  • autorefractometry,

Results

One thousand eight hundred eighty-two men and 2415 women were examined out of a total population of 5816, with an overall participation rate of 73.9%. The composition of the sample together with the participation rates according to sex and age have been analyzed in detail in a previous article.14 The participation rates were high for the age brackets between 40 and 79 years of age (65.4%–78.2%) and lower in more elderly subjects (38.6%), and participation was greater for women (75.8%) than for

Discussion

According to Van Herick et al’s15 classic article, anterior chamber peripheral depths corresponding to grades 2–1 and 0 of their method can be regarded as carrying a risk of occlusion. In the 26 patients with PACG, we found that the Van Herick grades 2–1 and 0 correspond, to a fair degree of approximation, to the angle width grades indicated with the same ratings according to Shaffer’s gonioscopic method. However, the Van Herick method represents only an approximation of the angular

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    This study was supported in part by Regione Trentino Alto Adige and Merck Sharp & Dohme Italy.

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