The biomechanical significance of pulley on binocular vision.
BACKGROUND
Pulleys have been reported as the functional origins of the rectus extraocular muscles (EOMs). However, biomechanical significance of pulleys on binocular vision has not been reported.


METHODS
Three eye movement models, i.e., non-pulley model, passive-pulley model, and active-pulley model, are used to simulate the horizontal movement of the eyes from the primary position to the left direction in the range of 1°-30°. The resultant forces of six EOMs along both orthogonal directions (i.e., the x-axis and y-axis defined in this paper) in the horizontal plane are calculated using the three models.


RESULTS
The resultant force along the y-axis of the left eye for non-pulley model are significantly larger than that of the other two pulley models. The difference of the force, between the left eye and the right eye in non-pulley model, is larger than those in the other two pulley models along x-axis and y-axis.


CONCLUSIONS
The pulley models present more biomechanical advantage on the horizontally binocular vision than the non-pulley model. Combining with the previous imaging evidences of pulleys, the results show that pulley model coincides well with the real physiological conditions.
Shanxi Key Laboratory of Material Strength and Structural Impact, Institute of Applied Mechanics and Biomedical Engineering, College of Mechanics, Taiyuan University of Technology, Yingze West Street 79, Taiyuan, 030024, Shanxi, China.
Hongmei
H
Guo
Shanxi Key Laboratory of Material Strength and Structural Impact, Institute of Applied Mechanics and Biomedical Engineering, College of Mechanics, Taiyuan University of Technology, Yingze West Street 79, Taiyuan, 030024, Shanxi, China.
Zhipeng
Z
Gao
Shanxi Key Laboratory of Material Strength and Structural Impact, Institute of Applied Mechanics and Biomedical Engineering, College of Mechanics, Taiyuan University of Technology, Yingze West Street 79, Taiyuan, 030024, Shanxi, China. chenweiyi211@163.com.
Weiyi
W
Chen
D001696:Biomechanical Phenomena; D005133:Eye Movements; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D015835:Ocular Motility Disorders / Q000503:physiopathology*; D009801:Oculomotor Muscles; D013314:Stress, Mechanical; D015348:Vision, Binocular / Q000502:physiology*; D014785:Vision, Ocular / Q000502:physiology
Equilibrium; Extraocular muscles; Force; Modeling; Vision