Abstract
Purpose: :
To describe change in refractive errors over a 5-year interval in an adult Japanese population sample, the Funagata Study.
Methods: :
This study is a sub-analysis of the Funagata study, a population based epidemiologic study of Japanese aged 35+ years. We used data from eye examinations performed in 2005-2006 as baseline (n=1122) and 5-year follow-up examination (2010-2011) (n=621; follow-up rate 55.3%). Non-cycloplegic refractive power was measured by an auto refractometer. Spherical equivalent (SE) was calculated as spherical power plus half of the cylindrical refraction. Change in SE over a 5-year interval was calculated as ‘SE (2010-2011) minus SE (2005-2006)’. Pseudo-phakic or aphakic eyes were excluded from this analysis. Physical activity, smoking, alcohol use and other life-style information (e.g., time of watching television per day) were collected from self-reported questionnaires. Associations of the mean change in SE over 5-year interval were determined using multiple linear regression models. We used logarithm transformed axial length in this analysis, because SE change over 5-year interval was deviated from normal distribution (Kolmogorov-Smirnov test p<0.01). We first analyze the data for right eyes, and then repeated them for left eyes to confirm the results from right eyes.
Results: :
Over the 5-year, mean SE change in baseline age groups of 35-44, 45-49, 50-54, 55-59, 60-64, 65-69, 70+ were -0.13D, -0.04D, 0.10D, 0.26D, 0.35D, 0.20D, -0.09D, respectively. Mean change in SE by baseline SE of <-5.0D, -5.0D to -0.5D, -0.5D to 0.5D and >0.5D, were -0.34D, 0.16D, 0.13D, 0.24D, respectively. Smaller baseline SE (-0.007D per -1D, 95%CI -0.009 to -0.004, p<0.001) was associated with negative SE change in 5 years after adjusting for age, sex and body height. In persons aged <55 years old, older age was associated with positive SE change (+0.002D per +1 year, 95%CI 0.001 to 0.003, p=0.002), while older age was associated with negative SE change in persons aged ≥65 years (-0.006D per +1 year, 95%CI -0.009 to -0.003, p<0.001) after adjusting for baseline SE, sex and body height. Age (-0.001D per +1 year, 95%CI -0.003 to 0.002, p=0.647) was not associated with SE changes over a 5-year interval in persons 55-64 years old. These findings were consistently observed when repeated with left eye data.
Conclusions: :
In this longitudinal study, persons aged <49 years old and persons aged ≥70 years old had negative SE changes, while persons 50-69 years old had positive SE changes. Persons with SE<-5.0D at baseline had negative SE changes over a 5-year interval. Negative SE changes in older persons (≥70) was correspond to previous study, however this is the new report that describe negative SE change in persons with high myopic SE (<-5.0D) and younger (<49).