The Prevalence of Glaucoma in an Urban Chinese Population in Taiwan a Pilot Study

Abstract

Aim: To estimate preliminarily the prevalence of glaucoma in an urban Chinese population 60 years and older and to evaluate the response rate for a further detailed glaucoma survey in Taiwan Method: The pilot study was conducted in a selected population unit of Taipei, Taiwan, in April and May 2001. All residents aged 60 years and over were invited for ocular examinations. Presenting and corrected visual acuities were measured using an illuminated Landolt C chart. Frequency doubling technology perimetry (FDP) was used for visual field screening. Goldmann applanation tonometer (GAT) was used for measuring intraocular pressure (IOP). Anterior chamber depth (ACD) was measured by optical Pachymetry and the van Herrick technique. Gonioscopy was carried out to confirm occludable angle. Finally, the cup to disc ratio (CDR) was estimated by slit lamp biomicroscopy using a 78D lens and eyepiece with measuring graticule (SLMP) after dilating the pupils. Results: Two hundred and ninety four subjects (67.0%) attended for eye examination equal to response rate 67%. The mean IOP in the population was 13.5mmHg (SD 2.9). ACD decreased with age and was significantly shallower in women and in cases with occludable angle. The prevalence of definite glaucoma was 4.42% (95% CI, 2.38-7.74) in the pilot study. The ratio of angle closure to open angle glaucoma was 7 to 5. There was one secondary glaucoma case. Two subjects were diagnosed as primary angle closure. The prevalence of glaucoma suspect was as followed: occludable angle 6.12%, ocular hypertension 1.70%, abnormal disc 1 .02% and glaucomatous visual field defect 0.68%. Conclusion: In the pilot study, the response rate was fairly good. Comparing to other ethnic population, the prevalence of angle closure glaucoma is rather high in Chinese in Taiwan. A further large-scale glaucoma survey should be conducted to give more precise figures for the prevalence of glaucoma.