The risk of developing age-related macular degeneration (AMD), the leading cause of vision loss in older adults, has decreased significantly for the baby boom generation.

The research, based on two studies conducted in Beaver Dam, Wis., was led by Karen Cruickshanks, PhD, professor of ophthalmology and visual sciences at the University of Wisconsin School of Medicine and Public Health. It showed that the risk of age-related macular degeneration (AMD) decreased by 60% for each generation since the “Greatest Generation” (those born between 1901 and 1924).

The findings were published in JAMA Ophthalmology journal.

Age-related macular degeneration is a disease that attacks the central part of the retina and causes a loss of central vision. With baby boomers now turning 65 at the rate of 10,000 per day, eye specialists worried that the number of AMD cases would skyrocket. But that seems not to be the case.

“We demonstrated that the five-year risk of developing AMD was dramatically lower for generations born later in the 20th century than those born earlier. We have extended these findings to the large group of baby boomers currently entering the older ages at which AMD presents,” said Cruickshanks. “Although we were unable to identify the factors that explained the change, this study suggests that modifiable factors contribute to the cause of AMD. Future research may uncover opportunities for primary prevention of this vision-threatening disorder.”

The authors write that during the 20th century, a number of significant changes took place that may have contributed to these improvements in the risk of non-communicable disease, including sanitation, housing, occupational safety, air and water quality and other environmental exposures. Some lifestyle and behavioral factors saw improvement, in addition to advances in the treatment and prevention of medical conditions and infectious diseases.

At the same time, however, obesity and sedentary lifestyles increased and economic conditions occasionally grew challenging. These latter factors prompted concern that that the gains made in some health conditions in previous generations may be slowing, flattening or disappearing and that people born during the baby boom and more recently may not continue to “age healthier” than their parents.

The incidence of age-related macular degeneration, adjusted for sex and age, was 8.8% among those in the Greatest Generation (1901-1924), 3% among the silent generation (1925-1945), 1% among the baby boom generation (1946-1964), and 0.3% among Generation X (1965-1984). Adjusting for age and sex and other risk factors, each generation was more than 60% less likely to develop AMD than the previous generation.

The data from the study came from two longitudinal group studies, the Beaver Dam Eye Study (a population-based study of residents of Beaver Dam, Wis.) and the Beaver Dam Offspring study (a study of their adult children), which included more than 4,800 adults. The participants were at risk for developing AMD based on eye images obtained when they entered the studies.

This was an observational study and thus cannot prove a cause-and-effect relationship.