The Prevalence and Types of Glaucoma in an Urban Chinese Population: The Singapore Chinese Eye Study.

IMPORTANCE

Glaucoma represents a major public health challenge in an aging population. The Tanjong Pagar Eye Study reported the prevalence and risk factors of glaucoma in a Singapore Chinese population in 1997, which established the higher rates of blindness in this population.

OBJECTIVES

To determine the prevalence and associated risk factors for glaucoma among Chinese adults in Singapore and to compare the results with those of the 1997 study. DESIGN, SETTING,

AND PARTICIPANTS

In a population-based survey of 4605 eligible individuals, we selected 3353 Chinese adults 40 years or older from the southwestern part of Singapore. Participants underwent examination at a single tertiary care research institute from February 9, 2009, through December 19, 2011.

EXPOSURES

All participants underwent slitlamp ophthalmic examination, applanation tonometry, measurement of central corneal thickness, gonioscopy, and a dilated fundus examination.

MAIN OUTCOMES AND MEASURES

Glaucoma as defined by the International Society of Geographical and Epidemiological Ophthalmology guidelines and age-standardized prevalence estimates computed as per the 2010 Singapore Chinese census. Blindness was defined as logMAR visual acuity of 1.00 (Snellen equivalent, 20/200 or worse).

RESULTS

Of the 3353 respondents, 134 (4.0%) had glaucoma, including primary open-angle glaucoma (POAG) in 57 (1.7%), primary angle-closure glaucoma (PACG) in 49 (1.5%), and secondary glaucoma in 28 (0.8%). The age-standardized prevalence (95% CI) of glaucoma was 3.2% (2.7%-3.9%); POAG, 1.4% (1.1%-1.9%); and PACG, 1.2% (0.9%-1.6%). In a multivariate model, POAG was associated with being older and male and having a higher intraocular pressure. Of the 134 participants with glaucoma, 114 (85.1%; 95% CI, 78.1%-90.1%) were not aware of their diagnosis. Prevalence (95% CI) of blindness caused by secondary glaucoma was 14.3% (5.7%-31.5%), followed by 10.2% (4.4%-21.8%) for PACG and 8.8% (3.8%-18.9%) for POAG. We could not identify a difference in the prevalence of glaucoma compared with the 3.2% reported in 1997 (difference, -0.04%; 95% CI, -1.2 to 1.2; P = .97).

CONCLUSIONS AND RELEVANCE

The prevalence of glaucoma among Singapore Chinese likely ranges from 2.7% to 3.9%, with secondary glaucoma being the most visually debilitating type. We could not identify a difference compared with previous studies approximately 12 years earlier. We report a high proportion of previously undiagnosed disease, suggesting the need to increase public awareness of this potentially blinding condition.