Abstract
Purpose::
While measurement of the amplitude of accommodation is a standard clinical procedure with well established norms in both children over 10 years of age and adults, there are only limited data specifying the normal findings in children under 10. For example, the classic studies of Donders and Duane contain little information for this particular age range. Accordingly, the aim of the present study was to determine the normal range of values for children between 5 and 10 years of age. These results are important for quantifying accommodative ability in this age group.
Methods::
The study was performed on 60 asymptomatic children between 5 and 10 years of age. Subjects were pediatric patients at the College of Optometry. After each child had been refracted for distance viewing, both push-up and push-down amplitudes were recorded from the right eye using an RAF nearpoint rule. An additional -5.00sph was introduced over the refractive correction to move the nearpoint away from the subject, thereby increasing the precision of the measurement. A detailed picture of a birthday cake was used as a target, with extra information including letters and words superimposed upon it. A total of 4 readings (2 push-up and 2 push-down measurements) were taken for each subject.
Results::
The mean findings (average of push-up and push-down) declined from 16.62D (SEM=2.07D) at 5 years of age to 11.60D (SEM=1.63D) at 10 years of age. Linear regression analysis showed a decline of 0.79D per year, which is considerably faster than the -0.30D per year change typically observed in adults. The difference between the push-up and push-down findings also declined with age, with the mean push-up finding being 0.86D higher than the push-down result at age 5, but only 0.64D higher at 10 years of age.
Conclusions::
Clinical measurements of amplitude of accommodation show a marked reduction between 5 and 10 years of age. Extrapolation of age-related data from studies performed on children over 10 years of age and adults to predict the findings in this younger population tend to underestimate the amplitude of accommodation. Accordingly, establishing clinically-based normative findings in this population is important.
Keywords: refraction • ciliary muscle