Ocular Biomechanics

The corneal biomechanics is used for describing disease states such as keratoconus, which leads to corneal deformation, and thinning, and affecting the mechanical behavior of the cornea. The corneal treatment effectiveness and efficiency depend on the connections between biological and biomechanical factors and their influences on the neigh-boring ocular tissues. Ocular biomechanics received huge interest over the last decade. At the turn of the century, methods to characterise the mechanical properties of the cornea and sclera ex-vivo have, to a large extent, been primitive and hence unable to produce accurate or reliable information on the tissue’s hyperelasticity, hysteresis, viscoelasticity or anisotropy, and the situation was even worse with in-vivo methods. Over the last 15 years, significant progress has been made on all fronts. There has been growing appreciation among clinicians and scientists alike of the importance of accurately characterising ocular tissue properties for customising treatment and management techniques for several conditions such as keratoconus, myopia and glaucoma. Methods to quantify the tissue’s response to mechanical actions ex-vivo have improved in sophistication and accuracy and become able to consider fully the dependence of mechanical behaviour on the distribution and orientation of collagen fibres. Numerical simulation saw huge advances to embed the material properties obtained in the laboratory in representative models of the eye and the clinical and surgical procedures applied to it. Methods to determine the tissue’s properties in-vivo have also received much attention and although we still do not have a working solution, we are not far from it. The expectations for ocular biomechanics over the medium and long term are very positive in terms of both better understanding of tissue’s behaviour in health and disease and the customisation of procedures, clinical and surgical, for individual patients. This edition casts some light on new developments in this field and provides examples of the progress being made.