Epidemiological survey of glaucoma among people over 40 years old in rural areas of Chongqing

Objective

To understand the prevalence and epidemiological characteristics of glaucoma among people over 40 years old in rural areas of Chongqing.

Methods

From August to October 2018, a stratified cluster random sampling method was used to investigate the cases of glaucoma among people over 40 years old in a rural population of the Rongchang and Qijiang Districts in Chongqing.The subjects had been living in the local area for over ten years.Basic information for each patient, including gender and age was documented, and their visual acuity and intraocular pressure were routinely measured.The Van Herick method was used to evaluate the depth of the central and peripheral anterior chamber, a preset lens was used to examine the fundus, and the cup to disc ratio(C/D) of the optic disc was emphasized.All suspected glaucoma patients underwent further standard glaucoma examinations.This study protocol was approved by the Ethics Committee of the First Affiliated Hospital of Army Medical University.

Results

A total of 4 680 people were identified, and 4 073 respondents participated in the survey, and the response rate was 87%.The prevalence of glaucoma was 1.72% (70/4 073). There were no significant differences in the prevalence of primary angle-closure glaucoma (PACG) and primary open angle glaucoma (POAG) between different genders (χ²=0.042, P=0.837; χ²=2.838, P=0.092). The prevalence of glaucoma in people over 70 years old was 2.5%, significantly higher than that in other age groups.In patients with glaucoma, the rate of visual impairment was 68.57%(48/70), and the rate of blindness was 47.14%(33/70). There was no significant difference in the incidence of low vision between different types of glaucoma (χ²=2.785, P=0.248), but there was a significant difference in the rate of blindness (χ²=10.668, P=0.005). The highest rate of blindness was found in secondary glaucoma.The detection rate of intraocular pressure, anterior chamber depth and C/D was statistically significant (χ²=43.325, P<0.001), and the positive rate of C/D was the highest.When the factors of intraocular pressure, and C/D were considered jointly, the detection rate of glaucoma could be increased to 55.88%.

Conclusions

The prevalence of glaucoma is 1.72% among people over 40 years old in rural areas of Chongqing, the prevalence of PACG is lower than previously recorded, but the proportion of glaucoma-induced visual impairment is higher.In field screening, the morphological examination of the fundus optic nerve is very important for the diagnosis of glaucoma.