Abstract
Purpose:
The aim of this study was to measure and compare the amplitude of accommodation, the accommodative facility and the vergence facility in a Swedish population of children with the existing normative data.
Methods:
One school in the middle of Sweden participated in this study. A total number of 42 children were tested but five children were excluded because of their reduced stereopsis, which left 37 children to participate. The children attended class two to six and were aged between 8.3 to 13.0 years (10.8 ± 1.4). The amplitude of accommodation was measured with Donders’ push-up method using a RAF ruler. Accommodative facility was tested over one minute period using a ±2.0 D flipper. Vergence facility was measured with a flipper of prism combination 3ΔBI/12ΔBO for one minute period. The two accommodative tests were done both monocular and binocular, in the order of right, left and binocular.
Results:
The mean amplitude of accommodation in this study was 13.5 ± 1.9 D. The binocular measurements was found to be similar with Hofsetter’s formula for average (18.5 - 0.3 * age) meanwhile the monocular values were significantly different from the same formula. A low but significant correlation was found between amplitude of accommodation and age. The mean value for the accommodative facility were 6.7 ± 4.4 cpm monocular and 5.5 ± 3.9 cpm binocular. There was no significant difference between OD, OS and OU (p > 0.05) nor between the classes (p > 0.05). The mean vergence facility in the study was 9.3 ± 3.8 cpm and there was no significant difference between the classes (p > 0.05).
Conclusions:
The binocular amplitude of accommodation agrees with the formula suggested by Hofstetter for the expected value but the monocular values in the study was lower. The accommodative facility was slightly lower when compared with other studies but agreed with the recommended data. The vergence facility in these children were lower than the normative data for adults.
Keywords: 404 accommodation •
751 vergence •
434 binocular vision/stereopsis