This paper deals with an efficient numerical method for the fully lubricated line contact between a rotating, deformable cylinder and a rigid surface. By exploiting the dynamic variation structure of this non-linear problem the deformation of and the pressure at the free, contact boundary are calculated. The dynamic formulation leads in a natural way to an iterative procedure, where the evoluti...

The purpose of this study was to determine the corneal epithelial alterations induced by various types of contact lenses. By employing the specular microscope, the corneal epithelia of 60 patients who had worn contact lenses for more than 1 year were re-examined along with 15 myopic controls. The morphological changes in aphakic patients who changed from extended wear soft to extended wear rigi...

BACKGROUND The aim of the study was to examine the clinical success of high Dk (oxygen permeability) piggyback contact lens (PBCL) systems for the correction of contact lens intolerant keratoconus patients. METHODS Sixteen patients (29 eyes) who were not able to wear gas-permeable rigid lenses were included in this study. Hyper Dk silicone hydrogel (oxygen transmissibility or Dk/t = 150 units...

Simulation of dynamic systems possessing unilateral frictional contacts is important to many industrial applications. While rigid body models are often employed, it is well established that friction can cause problems with the existence and uniqueness of the forward dynamics problem. In these situations, we argue that compliant contact models, while increasing the length of the state vector, su...

In this paper, we study the problem of predicting the acceleration of a set of rigid, 3-dimensional bodies in contact with Coulomb friction. The nonlinearity of Coulomb's law leads to a nonlinear complementarity formulation of the system model. This model is used in conjunction with the theory of quasi-variational inequalities to prove for the rst time that multi-rigid-body systems with all con...

Object manipulation is a basic element in everyday human lives. Robotic manipulation has progressed from maneuvering single-rigid-body objects with firm grasping to maneuvering soft objects and handling contact-rich actions. Meanwhile, technologies such as robot learning from demonstration have enabled humans to intuitively train robots. This paper discusses a new level of robotic learning-base...

OBJECTIVES The aim of this study was to measure tear film surface quality (TFSQ) using dynamic high-speed videokeratoscopy during short-term (8 hrs) use of rigid and soft contact lenses. METHODS A group of 14 subjects wore 3 different types of contact lenses on 3 different nonconsecutive days (order randomized) in 1 eye only. The subjects were screened to exclude those with dry eye. The lense...