The prevalence of appositional angle closure among adults aged 50 years or above in Funing county Jiangsu Province

Abstract

The purpose of the study is to determine the prevalence of appositional angle closure in persons aged 50 or above in Funing County. Cluster sampling randomly selected residents in Funing County aged 50 years or above. From March to May 2010, 484 eyes of 243 patients with the shallow peripheral anterior chamber and the anatomic narrow chamber angle, which was determined by Van Herick technique and gonioscopy, were collected from 5202 individuals. The presence of appositional angle closure and the angle-opening distance (AOD) was determined with photopic and scotopic ultrasound biomicroscopy (UBM) in eight positions. Paired χ² test and paired t test (SPSS 17.0) were used to determine any significant differences at P < 0.05. The prevalence of appositional angle closure was found at least one position in 337 eyes (69.6%) by scotopic UBM and in 116 eyes (24.0%) by photopic UBM. The prevalence of appositional angle closure was significantly higher by scotopic UBM than by photopic UBM (χ² = 204.36, P < 0.001 respectively), and was the highest in superior quadrant. The AOD varied significantly among the eight positions and was significantly narrower by scotopic UBM than by photopic UBM (t = 6.039, 6.883, 11.612, 11.157, 4.732, 6.798, 5.156, 4.071; P < 0.001). Since 197 persons (81.07%) were found anterior angle closure by scotopic UBM, we estimated the prevalence of appositional angle closure was 5.40% (95% CI: 4.80%-6.05%) among adults aged 50 or above in Funing County. The prevalence of appositional angle closure was higher than previous surveys, the possible reason is that scotopic UBM could find early appositional angle closure more preferably.