Differentiating Diagnosed and Undiagnosed Primary Angle-Closure Glaucoma and Open-Angle Glaucoma: A Population-Based Study.

PURPOSE: To study and compare factors contributing to the differentiation between diagnosed and undiagnosed primary angle-closure glaucoma (PACG) and primary open-angle glaucoma (POAG) in the same population.

DESIGN

Population-based survey.

PARTICIPANTS

All residents 40 years of age and older in Kumejima, Japan.

METHODS

Primary angle-closure glaucoma and POAG were diagnosed according to the criteria of the International Society of Geographical and Epidemiological Ophthalmology. Factors contributing significantly to the differentiation between diagnosed and undiagnosed PACG and POAG were selected from various systemic, ocular, visual function, and fundus planimetric parameters using multivariate logistic regression analysis and were compared between the two diseases.

MAIN OUTCOME MEASURES: Factors contributing significantly to the differentiation between diagnosed and undiagnosed PACG and POAG.

RESULTS

The prevalence rates of PACG and POAG were 2.2% and 4.0%, respectively. A greater proportion of patients with PACG (34.1%) received a diagnosis previously compared with patients with POAG (17.2%; P = 0.004). Worse mean deviation on visual field (VF) testing (odds ratio, 0.869; 95% confidence interval, 0.788-0.959; P = 0.006) and the presence of signs suggestive of previous acute angle closure (odds ratio, 4.35; range, 1.66-11.36; P = 0.003) contributed to a established diagnosis of PACG at the time of screening. A greater vertical cup-to-disc ratio (3.74; range, 1.38-10.17; P = 0.012) contributed with marginal significance to an established diagnosis of POAG at the time of screening.

CONCLUSIONS

Primary angle-closure glaucoma was more likely to have been diagnosed previously than POAG during a screening examination. Examination of the anterior segment and VF may contribute more to the detection of PACG, and disc examination may contribute more to the detection of POAG.