Purpose:
The Irish Nun Eye Study (INES) was designed to assess the prevalence of Age-related Maculopathy (ARM) in a community with a protected lifestyle. Information collected included demographic, medical, ophthalmic, dietary and UVR exposure data. We present the prevalence of ARM in this group.
Methods:
All participants had ophthalmic examination and stereo fundus imaging. The retinal images were graded at the Central Angiographic Reading Facility and classified according the Rotterdam Grading. Prevalence rates were calculated for stage of ARM and AMD. Indirect Standardised Age Specific Disease Rates (ISASDR) were calculated for comparison to the EurEye and Early Diseases Research Prevalence Group (EDRPG) data. UVR exposure was calculated using personal risk profile; exposure during childhood and adulthood, country, type of work and spectacle wear.
Results:
Gradable fundus images were available for 2430 eyes of 1242 individuals (97.8%). Data for the worst eye were used. The age range was 52 -100 years (mean 77) with 38.2% of the group being older than 80 years. Prevalence rates were grade 0, 60.5% (95% CI 57.7-63.2); grade 1, 21.4% (95% CI 19.2-23.8%); grade 2, 9.1% 95% (CI 7.7-10.9%);grade 3,3.0% (95% CI 2.1-4.1%); grade 4 (AMD ) 6.0% (95% CI 4.9-7.7%) Prevalence of geographic atrophy was 1.2% (95% CI 0.67-1.94%) and of neovascular AMD 4.8% (95% CI 3.7-6.1%). The ISASDR for stages 4a&b for those aged over 65 years for INES versus EurEye data was 85.4 (CI 36.1-109.7) which was lower but did not reach significance. For INES versus EDRPG the ISASDR was 78.4 (CI 61.4- 98.8) which was statistically significantly lower. The ISASDR for drusen >125um was 44.9 (CI 36.4 - 54.7) for INES versus EurEye and 45.0 (CI 36.5- 54.8) for INES versus EDRPG which was highly significantly less. There was no correlation of AMD grade with UVR exposure index.
Conclusions:
The age specific prevalence for AMD in INES is significantly less than in the EDRPG population. The prevalence of drusen >125um was significantly less than in both the EurEye and EDRPG studies. Although exposure to UVR did not correlate with disease severity, it is likely that other risk factors such as lack of smoking and significantly lower cardiovascular risk factors in the INES population are responsible for the reduced prevalence of AMD and large drusen in this group.
Keywords: age-related macular degeneration • clinical (human) or epidemiologic studies: prevalence/incidence • drusen