Open-angle Glaucoma in French Elderly Subjects: The Alienor Study

Abstract

Purpose: : To describe the prevalence of open-angle glaucoma in a sample of French subjects aged 73 years or more.

Methods: : The Alienor Study is a population-based epidemiological study on nutrition and age-related eye diseases. 963 subjects were recruited from September 2006 to May 2008. Glaucoma was classified according to the criteria of the ISGEO group. Vertical Cup:disc ratio (VCDR) and neuroretinal rim width:disc ratio (RDR) were measured from non-mydriatic digital colour photographs centred on the optic disc. The photographs were interpreted in double by two trained technicians and adjudicated by a specialist when inconsistent. Subjects were considered as suspect of glaucoma for VCDR >= 0.65 and/or asymmetry of VCDR >=0.2 and/or RCR <=0.1, in one eye at least. A complementary eye examination was performed in suspects, including visual field and gonioscopy. Finally, subjects were considered as affected by glaucoma when they combined structural (VCDR >=0.7 and/or asymmetry of VCDR >=0.2 and/or RCR<=0.1) and functional (visual field with a group of three non borderline points with p<0.01 of which at least one with p<0.005) evidence. We also classified five cases which did not completely meet these criteria (category 2 and 3 diagnosis of ISGEO). All cases of glaucoma were open angle.

Results: : Of the 963 included subjects, 944 (98 %) had gradable photographs in at least one eye. Of the 944 subjects, 86 (9.1 %) were classified as suspect. Of those, 76 subjects (88 %) underwent the additional examination for glaucoma. Finally, there were 891 subjects without glaucoma, 45 subjects with glaucoma and 27 subjects for whom glaucoma status could not be determined. Prevalence of glaucoma was globally 4.8 % (95 % confidence interval 3.4 % - 6.2 %). There was no difference between men and women (4.9 % and 4.5 %, respectively), while the prevalence increased from 3.7 % (2.1 % - 5.3 %) in subjects younger than 80 years to 5.8 % (3.6 % - 8.0 %) in subjects older than 80 years. Of 45 cases of glaucoma, 18 (40 %) were not diagnosed previously.

Conclusions: : The prevalence rates of glaucoma observed in this sample is similar to those usually observed in elderly subjects of Western countries, supporting the hypothesis that our sample is not highly biased. This study further confirms the high rate of undiagnosed glaucoma in industrialized countries.

Keywords: clinical (human) or epidemiologic studies: prevalence/incidence • aging