The Influence Of Head Tilt On Fovea-disc Angle On Patient With Inferior Oblique Hyperfunction

Objective: To explore the the influence of muscle dysfunction and compensatory head on fovea disc angle degree(FDA) on The influence of head tilt on fovea-disc angle on patient with Inferior oblique hypofunction, vertical prism degree and head tilt degree have relationship or not, what’s the significant variation of FDA.Methods: This experiment has included 25 patients(50 eyes) of inferior oblique hypofunction or superior oblique palsy, using three prism measured vertical prism; patients were asked to watch the same the same near visual chart, using the angle- ruler to measured its head-tilt position; using 3DOCT-1000 for subjects with normal shooting, compensatory head position, head right 30 degrees, left head 30 degrees fundus photography, and use the software for measuring FDA value.Results: The FDA of diseased eyes is:9.03 + 3.67 degrees, and the FDA of healthy eye group was :9.35 + + 4.06 degrees. The mean value of FDA and the maximum FDA value(7.43 degrees) of the normal eye in the diseased eyes and healthy eyes were tested by independent samples t test, the results were p=0.024 < 0.05, p=0.048 < 0.05, respectively. Paired t test of FDA was performed on the right position and the compensatory head position in the lower eye and the high eye: the former P < 0.01, t=-11.16, the latter P < 0.01, t=11.22, the difference was statistically significant. The correlation analysis between the degree of vertical prism and the compensation of the tilt of the head circumference, the correlation coefficient is 0.574, a significant correlation, p=0.003 < 0.05, with statistical significance. The changes of FDA in patients when head was tilted 30 degrees were tested by paired t test between The healthy and ill side,and before and after the operation,, p=>0.05, which was not statistically significant.Conclusion: If there were no abnormal oblique muscles in the contralateral eye, the FDA of the contralateral eye was also different from that of the normal subjects. Compensatory head position has a significant impact on FDA, the clinical application of fundus photography to assess the patient’s fundus rotation state should be with close attention to the head position is positive. There was a significant correlation between the degree of vertical strabismus and the tilt of the head, which is helpful to confirm the mechanism of the compensatory head position, including helping or reducing the distance of the complex image. The function of obliques has no significant effect on the FDA changes。When the head is tilted 30°,the torsion of eyes is significantly smaller than 30°.