Changes in Refraction Over 10 Years in an Adult Population: The Beaver Dam Eye Study
The purpose of this study is to quantify the 10-year change in refraction in persons more than 40 years of age.
All people 43 to 84 years of age and living in Beaver Dam, Wisconsin, in 1988 were invited for a baseline examination (1988-1990), a 5-year follow-up examination (1993-1995), and a 10-year follow-up examination (1998-2000).
After adjustment for the severity of nuclear sclerosis and other factors, the 10-year change in refraction was +0.48, +0.03, and -0.19 D for persons 43 to 59, 60 to 69 and 70+ years of age at the baseline examination, respectively.
Severity of nuclear sclerosis was also strongly related to amount of change.
Those with mild nuclear sclerosis at baseline had a change of +0.35 D, whereas those with severe nuclear sclerosis had a change of -0.53 D. The amount of change was also related to diabetes and weakly related to baseline refractive error, but was unrelated to gender and education.
In addition to the longitudinal changes observed, there was a birth cohort effect. In comparing people of the same age across examinations, those born in more recent years had more myopia than those born in earlier years.
Significant changes in spherical equivalent in adults occur over a 10-year period. Younger people became more hyperopic, whereas older people became more myopic. These data provide evidence of a longitudinal change in refraction in adults, which may explain the refractive patterns observed in cross-sectional studies.