Elsevier

Ophthalmology

Volume 119, Issue 4, April 2012, Pages 759-764
Ophthalmology

Original article
A Population-based Survey of the Prevalence and Types of Glaucoma in Nepal: The Bhaktapur Glaucoma Study

https://doi.org/10.1016/j.ophtha.2011.10.021Get rights and content

Objective

To determine the prevalence and types of glaucoma in a Nepalese population.

Design

Cross-sectional, population-based survey.

Participants

A total of 4800 subjects aged 40 years or older from the Bhaktapur district of Kathmandu valley.

Methods

Subjects aged 40 years or older were selected using a cluster sampling procedure and door-to-door enumeration for a population-based, cross-sectional study. All subjects underwent a detailed ocular examination at the base hospital, which included logarithm of minimal angle of resolution visual acuity, refraction, applanation tonometry, gonioscopy, Lens Opacities Classification System II cataract grading, retinal examination, and Swedish Interactive Thresholding Algorithm standard perimetry when indicated.

Main Outcome Measures

Diagnosis of glaucoma was based on criteria described by the International Society for Geographic and Epidemiological Ophthalmology.

Results

A total of 4003 subjects underwent a comprehensive eye examination (response rate 83.4%), and complete data were available in 3991 subjects. The mean intraocular pressure was 13.3 mmHg (97.5th and 99.5th percentiles, 18 and 20 mmHg, respectively), and the mean vertical cup-to-disc ratio was 0.26 (97.5th and 99.5th percentiles, 0.6 and 0.8 mmHg, respectively). There were 75 subjects with glaucoma, an age- and sex-standardized prevalence of 1.80 (95% confidence interval [CI], 1.68–1.92). Age- and sex-standardized prevalence was 1.24% (95% CI, 1.14–1.34) for primary open-angle glaucoma (POAG), 0.39% (95% CI, 0.34–0.45) for primary angle-closure glaucoma (PACG), and 0.15% (95% CI, 0.07–0.36) for secondary glaucoma. The prevalence of glaucoma increased with an increase in age with no significant difference in gender. Primary angle-closure glaucoma was 3 times more common in women. Nine eyes were blind, and 2 subjects were bilaterally blind from glaucoma.

Conclusions

The overall prevalence of glaucoma was 1.9%. Of all glaucoma cases, POAG accounted for 68%, PACG accounted for 22.67%, and secondary glaucoma accounted for 9.33%. Among the subjects with POAG, 96.08% had not been previously diagnosed.

Financial Disclosure(s)

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

Section snippets

Study Design

The rationale, methods, and baseline demographics of BGS have been published in detail.12 In brief, the survey involved the selection of 4800 subjects aged 40 years or older residing in the Bhaktapur district.

A 2-stage World Health Organization 30-cluster sampling procedure was adopted for patient selection.13 The sampling frame comprised 161 wards and an estimated population of 48 223 people aged more than 40 years.14 In the first stage, 30 wards were selected and field workers conducted a

Results

The distribution of IOP and VCDR from subjects with a normal result on suprathreshold field screening in both eyes of the nonglaucomatous population is shown in Table 2. This includes the 97.5th and 99.5th percentile points used in allocating diagnoses.

Of 4800 enumerated subjects, 4003 were examined (response rate, 83.39%). Data were incomplete for 12 subjects, leaving 3991 for analysis (83.15%). The mean age of the study population was 55.08 years (standard deviation, 11.50 years), and more

Discussion

The BGS is the first study in Nepal to report the prevalence of glaucoma based on the ISGEO criteria and is therefore comparable to other studies around the world that follow the same criteria.

The median IOP of 13.0 mmHg was similar to that in studies from the region8, 10, 18, 19 but lower than in reports on the Caucasian population.20, 21 The median VCDR was 0.20 (97.5th percentile, 0.6 mmHg). We recommend that a VCDR of >0.6 be viewed with suspicion for glaucoma in our population. The West

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    Manuscript no. 2011-542.

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

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