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Minus-lens stimulated accommodative amplitude decreases sigmoidally with age: A study of objectively measured accommodative amplitudes from age 3.

Anderson HA, Hentz G, Glasser A, Stuebing KK, Manny RE

College of Optometry, University of Houston, 505 J Davis Armistead Bldg, Houston, Texas, 77204-2020, United States.

Purpose Guidelines for predicting accommodative amplitude by age are often based on subjective push-up test data which overestimate the accommodative response. Studies using objective measurements have defined expected amplitudes for adults, but expected amplitudes for children remain unknown. This study used objective methods to measure accommodative amplitude for a wide age range of individuals to define the relationship of amplitude and age from age 3. Methods Accommodative responses were measured in 140 subjects aged 3-40. Measurements were taken with the Grand Seiko autorefractor as the subjects viewed a high contrast target at 33 cm through minus lenses of increasing power until responses showed no further increase in accommodation. Results Maximum accommodative amplitude of each subject was plotted by age and a curvilinear function fit to the data (y = 7.33-0.0035*(Age-3)(2), p<0.001). Tangent analysis of the fit indicated accommodative amplitude remains relatively stable until age 20. Data from this study were then pooled with objective amplitudes from previous studies of adults up to age 70. A sigmoidal function was fit to the data (y=7.0829 / (1+e((0.2031*((age-36.2)-0.6109)))), p<0.001). The sigmoidal function indicated relatively stable amplitudes below age 20, a rapid linear decline between 20 to 50, and a taper to zero beyond 50. Conclusions These data indicate accommodative amplitude decreases in a curvilinear manner from 3 to 40. When combined with data from previous studies a sigmoidal function describes the overall trend throughout life with the biggest decrease occurring between 20 to 50 years.

Published 10 March 2008 in Invest Ophthalmol Vis Sci.
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