MATHEMATICAL MODELLING OF BLEPHAROPTOSIS: MECHANISM AND APPLICATION
Ruoyu Huang (University of Strathclyde)
Thursday 6th February, 2020 14:00-15:00 Maths 311B
Blepharoptosis (or ptosis) refers to a drooping of the upper eyelid. Simple congenital blepharoptosis is caused by muscle dysgenesis, i.e. reduction of the contraction function of muscle due to abnormal development of collagen fibres known as fibrosis. The diagnosis and surgery to successfully treating ptosis have been facing two major challenges: a complete preoperative evaluation and a precise prediction of the long-term effect of an individual surgery.
The core of the research is to address a typical challenge in biomechanics, i.e. to understand the multiscale structure and function of the soft tissues and to predict post-operative behaviours. At the tissue scale, the eyelid is a structure assembled by different components including ligaments and tendons as the framework/reinforcement and levator muscle (skeletal muscle) and Muller’s muscle (smooth muscle) as the active components. At the microstructure scale, collagen fibres and skeletal/smooth muscle fibres interact to maintain the strength and function of the tissue.
Preliminarily, the present study aims to address two long-term key open questions in the anatomy and surgery, i.e. the roles of Whitnall’s ligament and Muller’s muscle in eyelid motion and ptosis. Mathematical model was proposed to clarify the mechanism of the motion of eyelid as a whole. We calculated the force and energy to complete such a motion, which would be useful for biomechanical tests and clinical applications.
For more realistic modelling, finite element analysis (FEA) has been conducted using the suitable constitutive models in which fibres play the key role in regulating the function and morphology of the eyelid.