Accommodative adaptation in children.

Abstract

Although accommodative adaptation has been studied extensively in young adult populations, there has been little consideration of this function in children. Accordingly, we examined accommodative adaptation by comparing pre- and post-task measurements of dark accommodation (DA) in children and young adults. DA was assessed objectively before and immediately after a 5-min near-vision task (viewing distance = 20 cm) using an open-field, infrared optometer (Canon Autoref R-1). The study was performed on 15 visually normal children (mean age = 10.1 years) and 10 visually normal young adults (mean age = 25.2 years). No significant difference was observed between the mean values of pre-task DA for the two age groups (children = 1.01 D, adults = 0.88 D). Both groups showed equivalent degrees of accommodative adaptation (approximately 1.0 D), and the rate of regression of post-task DA to the pre-task level was similar for each group. We found a significant positive correlation between the magnitude of adaptation and pre-task DA in children, which was not found in the young adult population. The results indicate that pre-task DA and accommodative adaptation (both in terms of magnitude and rate of decay) are similar in adults and children. This would not support the proposal that the development of nearwork-induced myopia in children is related to short-term variations in accommodative adaptation when compared with young adults.