Six-Year Incidence and Risk Factors of Primary Glaucoma in the Singapore Indian Eye Study

Incidence of primary open angle glaucoma in the Andhra Pradesh Eye Disease Study (APEDS)

BACKGROUND

To report 15-year incidence rate of primary open angle glaucoma (POAG) in the Andhra Pradesh Eye Disease Study (APEDS).

METHODS

A population-based longitudinal study was carried out at three rural study sites. Phakic participants aged ≥40 years who participated at baseline (APEDS I) and the mean 15-year follow-up visit (APEDS III) were included. A comprehensive ophthalmic examination was performed on all participants. Mean intraocular pressure (IOP) was average of IOPs of right and left eyes. The definition of glaucoma was based on the International Society of Geographical and Epidemiological Ophthalmology (ISGEO) classification. The main outcome measure was incidence of POAG during the follow-up period in participants without glaucoma or suspicion of glaucoma at baseline.

RESULTS

Data from the available and eligible participants from the original cohort (1241/2790; 44.4%) were analysed. The mean age (standard deviation) of participants at baseline was 50.2 (8.1) years; 580 (46.7%) were men. Thirty-six participants developed POAG [bilateral in 17 (47.2%)] over 15 years. The incidence rate of POAG per 100-person years (95% confidence interval) was 2.83 (2.6, 3.08). Compared to baseline, the reduction in mean IOP [median (range) mm Hg] was -0.75 (-7.5, 9) in participants with incident POAG and -2.5 (-14.5, 14.5) in those without. The inter-visit difference in mean IOP was a significant risk factor on logistic regression analysis.

CONCLUSION

We report the long-term incidence of POAG in rural India. A longitudinal change in IOP, specifically a less pronounced reduction in IOP with increasing age, was a novel risk factor.

The Beijing angle closure progression study: design and methodology

Purpose

The purpose of this study is to summarize the design and methodology of a large-scale trial in northern China, the Beijing Angle Closure Progression Study (BAPS). This trial is designed to explore the 5-year incidence of primary angle-closure suspect (PACS) progressing to primary angle-closure (PAC) or primary angle-closure glaucoma (PACG) and to determine the possible risk factors of disease progression.

Methods/design

The BAPS is a clinic-based, multicenter, noninterventional trial conducted on a sample of urban Chinese adults. Consecutive eligible patients who meet PACS diagnostic criteria will be recruited from eight participating centers, with the trial commencing on August 4, 2022. The target sample size is set at 825 subjects, with follow up planned for a minimum period of 5 years. Baseline examination will include presenting visual acuity, best corrected visual acuity, intraocular pressure (IOP), undilated slit-lamp biomicroscopy, stereoscopic evaluation of the optic disc, visual field test, optical coherence tomography evaluation of retinal nerve fiber layer, ultrasound biomicroscopy and IOLMaster. Questionnaires will also be used to collect detailed personal history. Patients are scheduled to visit the glaucoma clinic every 12 months and may visit the emergency room in case of acute attack of angle closure. Study endpoints include acute PAC episodes, elevated IOP, peripheral anterior synechiae, glaucomatous visual field defect, or glaucomatous abnormality of optic nerve.

Discussion

The BAPS will provide data on the 5-year incidence of PACS progressing to PAC or PACG and determine the risk factors for disease progression. This study will also help redefine high-risk patients with PACS.

Five-year incidence of primary glaucoma and related risk factors - The Handan eye study

PURPOSE

To determine the 5-year incidence of primary glaucoma and its associated risk factors in rural northern China.

METHODS

Population-based cohort study. A total of 5184 participants aged 30 years and older, without glaucoma at baseline, were subjected to comprehensive standardized interviews and ophthalmic and systemic examinations at baseline and after a 5-year interval in the Handan Eye Study. Incident glaucoma was diagnosed by a consensus panel of five senior glaucoma specialists. Univariate and multivariable logistic regression analyses were performed to identify the baseline risk factors that could predict the incidence of glaucoma.

RESULTS

During the 5-year follow-up, incident primary glaucoma developed in 82 subjects (1.6%; 95% confidence interval [CI], 1.2%-1.9%). The age- and gender-standardized incidence of glaucoma among subjects ≥40 years old was 2.1% (0.4% annually), calculated according to the 2010 Chinese census. A higher age (odds ratio [OR], 1.06; 95% CI, 1.04-1.09; p < 0.001), higher intraocular pressure (IOP) (OR, 1.11; 95% CI, 1.02-1.20; p = 0.017), and vertical cup disc ratio (VCDR) ≥ 0.60 (OR, 5.30; 95% CI, 3.22-8.73; p < 0.001) were found to be associated with an increased risk of incident glaucoma. For each year, older age and each mmHg higher IOP, the risks of primary glaucoma increased by 1.2% and 2.0% per year, respectively.

CONCLUSION

We reported the 5-year incidence of primary glaucoma in a rural Chinese population and found that older age, higher IOP, and VCDR ≥ 0.60 at baseline could help in identifying those at highest risk of disease development.

Asian Race and Primary Open-Angle Glaucoma: Where Do We Stand?

Primary open-angle glaucoma (POAG) is an optic neuropathy characterized by irreversible retinal ganglion cell damage and visual field loss. The global POAG prevalence is estimated to be 3.05%, and near term is expected to significantly rise, especially within aging Asian populations. Primary angle-closure glaucoma disproportionately affects Asians, with up to four times greater prevalence of normal-tension glaucoma reported compared with high-tension glaucoma. Estimates for overall POAG prevalence in Asian populations vary, with Chinese and Indian populations representing the majority of future cases. Structural characteristics associated with glaucoma progression including the optic nerve head, retina, and cornea are distinct in Asians, serving as intermediates between African and European descent populations. Patterns in IOP suggest some similarities between races, with a significant inverse relationship between age and IOP only in Asian populations. Genetic differences have been suggested to play a role in these differences, however, a clear genetic pattern is yet to be established. POAG pathogenesis differs between Asians and other ethnicities, and it may differ within the broad classification of the Asian race. Greater awareness and further research are needed to improve treatment plans and outcomes for the increasingly high prevalence of normal tension glaucoma within aging Asian populations.