Horizontal and Vertical Fusional Amplitudes in Normal Eyes

ABSTRACT

Fusional amplitudes can be measured using various clinical techniques and targets. But the vergence ranges are different according to the used instruments and the environmental conditions. Currently, measurement with the prism is usually llsed but this method have wide vardabele ranges by the used targets and environmental settings. The authors measured the vertical and horizontal fusional amplitudes of 135 normal Korean men with rotary prism in a well-lit office and compared the group using dim light targer with the group using small letter target. In the group using dim light target, true far convergence value was 14.67 +/- 6.24 delta, true far divergence was 6.64 +/- 3.48 delta, true near convergence was 24.96 +/- 7. 33 delta, true near divergence was 11.05 +/- 5.13delta, far vertical vergence was 2.93 +/-0.95 delta, and near vertical vergence was 3.40 +/- 1.15 delta, There was no statistical differences among are groups(p>0.05), and between the groups using small letter target and dim light target in true near and far convergence amplitudes (p>0.05). This study shows that the method using dim light target is simple and valuable method in measuring the fusional vergences.