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H. A. Anderson, K. K. Stuebing, A. Glasser, R. E. Manny; Influence of Accommodative Amplitude and Age on Objective Measurements of Lag in Children and Adults. Invest. Ophthalmol. Vis. Sci. 2008;49(13):4560.
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© ARVO (1962-2015); The Authors (2016-present)
Previously reported data from this lab demonstrates that objectively measured, trial lens stimulated amplitudes of accommodation are largest in young children (mean predicted ampl=7.33D) and remain relatively stable from age 3 until the 20s when amplitude begins to decline rapidly with age. The purpose of this study is to investigate the influence of age and amplitude upon lag of accommodation.
Accommodative responses were measured in 101 subjects (3-40 yrs) with at least 10 subjects in each 5yr age bin. Subjects monocularly viewed a high contrast target with small print and pictures positioned at 33.3 cm on the near rod of the Grand Seiko autorefractor. Refractions were measured as the subject kept the target clear. Accommodative lag was defined as the difference between demand and response. Four additional demands were tested by introducing minus lenses of increasing power in the spectacle plane of the viewing eye. Accommodative demands and responses were adjusted to the corneal plane to account for lens effectivity.
At the 3D demand, the most accurate accommodative response was observed in subjects 26-30 yrs (mean lag 0.49±0.26D) and the least accurate responses observed in the youngest subjects (0.94±0.29D). As the stimulus demand approached the maximum response amplitude for the 26-30yr group (mean predicted ampl=5.83D), lag increased and the most accurate responses shifted to the 16-20 yr group (0.96±0.51 for 6.52D demand). When response amplitude was essentially constant (3-20 yrs), lag of accommodation was always greatest in the youngest subjects for all demands and decreased systematically with increasing age. When accommodative response was not limited by the response amplitude, the largest mean difference between the most accurate response and the highest lag was 1.06D and occurred for the 4.80D stimulus (mean lag 1.74±0.77D ages 3-5, versus 0.68±0.38D ages 26-30).
Accommodative lag systematically decreased from the youngest subjects until the 20s for all five stimulus demands tested and suggests that the accuracy of the accommodative system varies throughout childhood independent of the stable accommodative amplitude that is present throughout these years.
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