THE BEAVER DAM EYE STUDY (BDES)
The Beaver Dam Eye Study is funded by the National Eye Institute, one of the 20 National Institutes of Health. The purpose of the study is to collect information on the prevalence and incidence of age-related cataract, macular degeneration and diabetic retinopathy, which are all common eye diseases causing loss of vision in an aging population. The study was designed to discover (or detect) causes of these conditions. The study also has examined other aging problems, such as decline in overall health and quality of life and development of kidney and heart disease.
The study was initially funded in 1987. A private census was conducted in the city and township of Beaver Dam, Wisconsin, and found that there were approximately 6000 people aged 43 through 84 years. Approximately 5000 of them participated in the baseline examination between 1988 and 1990. Five-, 10-, 15-, and 20-year follow-up examinations have taken place and 3700, 2800, 2100, 2000, and 1900 people participated in each of the respective examination phases. A 25-year follow-up examination is currently underway.
So far, the Beaver Dam Eye Study has produced more than 360 publications describing the prevalence and incidence of visual loss, age-related macular degeneration, cataract, and associated risk factors. An important finding from the study is the association of cigarette smoking with both cataract and age-related macular degeneration. Another important finding is the description of the relationship of early abnormalities such as retinal drusen and increased and decreased retinal pigment with the progression to late stages of age-related macular degeneration. This information has been used to provide estimates of these conditions in the general population, to develop protocols, and to provide estimates on the number of participants needed to conduct large clinical trials on age-related macular degeneration.
Systems were developed to image (photograph) parts of the eye involved in cataract and age-related macular degeneration. A standard scale was developed in the Beaver Dam Eye Study to describe the severity of these abnormalities. The imaging systems and standard scale developed by the Beaver Dam Eye Study have been used in other epidemiological studies of these eye diseases including, the Blue Mountains Eye Study in Australia, the Rotterdam Study in the Netherlands, and the Los Angeles Latino Eye Study. These studies have also adapted protocols developed by the Beaver Dam Eye Study. Comparisons of the data from the Beaver Dam, Blue Mountains, and Rotterdam studies showed that despite a number of differences in exposures among the populations, the prevalence of late stages of age-related macular degeneration were similar. The strong association of cigarette smoking and macular degeneration was found in all three populations.
The Beaver Dam Eye Study began its sixth round of eye examinations in the spring of 2014. The objective of this follow-up examination is to determine the relationships of modifiable risk factors, e.g., a marker of advanced glycation endproducts, oxidative stress, and markers of inflammation and atherosclerosis to the incidence of age-related macular degeneration (AMD). It will examine the epidemiology of anatomic and functional features of the retina using spectral-domain optical coherence tomography and frequency doubling technology perimetric measurements across the full spectrum of AMD in the general population. The study hopes to substantially advance knowledge of AMD and other ocular conditions and allow translation of new knowledge into interventions resulting in improved health for future generations of the general population as they age.