Biomechanical analysis of x-pattern exotropia.

Purpose: To simulate and check the plausibility of the proposed mechanisms of X-pattern exotropia and to determine the least invasive surgical method that can be used to treat the disorder.

Design: Computational supported analysis and retrospective study.

Methods: The oculomotor model SEE++ was used to simulate the effects of the different causes that have been proposed for the X-phenomenon.

Computer-assisted dosage calculation for strabismus therapy in myopic patients.

Purpose: The published dosage recommendations for the surgical correction of horizontal strabismus in non-myopic patients show large, unexplained differences. For patients with high myopia, the situation becomes even more complex because the increase in the size of the bulb also affects the geometry of the oculomotor muscles. In this study, we wanted to investigate whether computer simulations of the oculomotor plant can be used to find accurate surgical parameters.

A comparison of two different techniques for oculomotor torque reduction.

Purpose: To compare the results of two different surgical techniques: 'Cüppers technique', in which the torque of oculomotor rectus muscles is reduced by suturing the muscle to the globe in the posterior half of the globe; and 'Y-split recessions', in which the muscle torque is reduced by Y-splitting the rectus muscles, and reattaching the two halves at an angle to each other.

Methods: We carried out a retrospective analysis of the outcome of surgery on 100 patients with infantile esotropia.

Results: Both techniques show a sufficient reduction of strabismus angle variability, and minimal and maximal strabismus angle.

Model-based improvements in the treatment of patients with strabismus and axial high myopia.

Purpose: Eye motility disorders with axial high myopia and an enlarged globe are often characterized by a hypotropia of the affected eye, usually referred to as heavy-eye syndrome. Based on an intuitive interpretation of magnetic resonance (MR) images, the cause of the hypotropia has typically been assigned to the rectus muscles. In this study, the hypothesis that the oblique muscles play an important role in the underlying biomechanical disorder of this type of strabismus was investigated.

SEE++: a biomechanical model of the oculomotor plant.

The consequences of changes in the oculomotor system on the three-dimensional eye movements are difficult to grasp. Although changes to the rectus muscles can still be approximately understood with simplified geometric models, this approach no longer works with the oblique muscles. It is shown how SEE++, a biomechanical model of the oculomotor plant that was built on the ideas of Miller and Robinson (1984) can improve the understanding of the effects of changes to the oblique eye muscles.