Abstract
Purpose :
The purpose of this study was to investigate accommodative accuracy and stability in young children with uncorrected hyperopia and adults as control subjects.
Methods :
Accommodation was measured using photorefraction (25 Hz) in 54 children (3-10 yrs) with uncorrected hyperopia and age normal VA and binocular vision and in 8 adults (23-31 yrs) with normal VA without correction. Subjects viewed 20/50 sized stimuli at 33cm during a 10 minute active and passive task (order randomized). Active task: Subjects <6 yrs and 6 yr olds unable to read, viewed shapes while answering questions about the shapes (Group 1, n = 31). Subjects ≥6 yrs read passages at their reading level and answered questions upon completion (Group 2, n = 23). Adults read portions of an economics dissertation and answered questions upon completion. Passive task: Group 1 viewed shapes, Group 2 and adults viewed rows of letters. Mean accommodative lag and stability (in the time [root mean square RMS] and frequency domain [low frequency component (LFC) 0-<0.6Hz]), were calculated. Two-factor repeated measures ANOVA with post hoc analysis (Holm Sidek) compared accommodation within and across groups for both viewing conditions.
Results :
Both groups of children had larger lags (p<0.05), RMS (p<0.001) and LFC (p<0.001) in the passive versus active condition. A difference in lag was not detected in adults between the two conditions (p=0.99), but RMS (p=0.030) and LFC (p=0.003) were significantly larger during passive viewing. Group 1 had significantly larger lags than Group 2 (p=0.008) and adults (p=0.005) for the passive condition and larger lags than Group 2 (p=0.039), but not than adults (p=0.137) for the active condition. A difference in lag was not detected between Group 2 and adults in either task (p>0.05). RMS and LFC decreased significantly across groups in order of increasing age for both tasks (p<0.05), with the exception that Groups 1&2 had similar RMS in the active task (p=0.144).
Conclusions :
These data suggest that on average, the accommodative response is less accurate and more variable in children when passively viewing a stimulus than when actively viewing a stimulus. Additionally, for the majority of comparisons, children <10 yrs with uncorrected hyperopia did not have adult-like accommodative behavior (accuracy or stability) under passive or active viewing.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.