Abstract
Purpose: :
To estimate the prevalence of primary angle-closure glaucoma (PACG), primary angle closure (PAC), primary angle closure suspect (PACS) and associated risk factors in the Indian state of Andhra Pradesh
Methods: :
A population-based study using a stratified, random, cluster, systematic sampling strategy, was conducted in the state of Andhra Pradesh in India during 1996 to 2000. Participants from 94 clusters in one urban and 3 rural areas representative of the population of Andhra Pradesh underwent a detailed interview and a comprehensive ocular evaluation that included logarithm of minimum angle of resolution visual acuity, refraction, split lamp biomicroscopy, applanation tonometry and gonioscopy. Gonioscopy was performed with NMR-K 2 mirror gonio lens under appropriate testing conditions to define occludability before manipulating gonioscopy to visualize the angle structures. In participants with occludable angles pupils were not dilated. All other participants underwent pupilary dilatation and detailed fundus evaluation. Humphrey full threshold 24-2 visual fields were performed when indicated by standardized criteria for disc cupping or if intraocular pressure was more than or equal to 22 mm of Hg. Trained professionals performed all examinations. Angle closure disease was diagnosed and categorized using International Society of Geographical and Epidemiological Ophthalmology criteria
Results: :
PACG was present in 35 of 3724 subjects, an age and gender adjusted prevalence of 0.94% (95% CI: 0.7%, 1.3%) among subjects ≥ 40 years. PAC was present in 12(0.3%, 95% CI: 0.1%, 0.5%) and PACS in 71 (2%, 95% CI: 1.5%, 2.4%). Diagnosis of PACG was based on category I in 28, category II in 4 and category III in 3 subjects. PAC was diagnosed based on IOP in 3 and gonio synechiae in 9 subjects. The prevalence of PACG and PAC combined was 1.26% (95% CI: 1.02, 1.62%). Forty four of the 47 (93.6%) patients with PACG or PAC were not aware of their disease. The prevalence of blindness due to PACG was 28.6% (10/35). Increase in intraocular pressure was significantly associated with PACG (P < 0.001, odds of 1.29 (95% CI: 1.19, 1.40). No significant association was found with systemic hypertension, socio economic status and hyperopia. Diabetes mellitus (P= 0.009, odds ratio 3.19 (95% CI: 1.34, 7.58) and female gender (P=0.025, odds ratio 2.07, 95%CI: 1.09, 3.93) were risk factors for angle closure disease
Conclusions: :
The prevalence of PACG in this population was 0.94%. Diabetes and female gender were the risk factors. Blindness due to PACG was 28.6%
Keywords: clinical (human) or epidemiologic studies: biostatistics/epidemiology methodology