Short-Time Changes of Intraocular Pressure and Biomechanics of the Anterior Segment of the Eye during Water Drinking Test in Patients with XEN GelStent.

Purpose: Little is known about short-term changes in intraocular pressure (IOP) following minimally invasive glaucoma surgeries, such as post-XEN GelStent implantation. Although the importance of corneal biomechanics in glaucoma diagnostics has been reported, little work has been conducted on postoperative description of changes when the structure of the anterior segment is altered. The aim of presented study was to evaluate the changes in the biomechanical parameters of the anterior segment of the post-XEN GelStent implantation eyes.

How a dynamic optical system maintains image quality: Self-adjustment of the human eye.

The eyeball is continually subjected to forces that cause alterations to its shape and dimensions, as well as to its optical components. Forces that induce accommodation result in an intentional change in focus; others, such as the effect of intraocular pressure fluctuations, are more subtle. Although the mechanical properties of the eyeball and its components permit mediation of such subtle forces, the concomitant optical changes are not detected by the visual system.

Finite element simulation of Goldmann tonometry after refractive surgery.

Background: The problem of accuracy of intraocular pressure (IOP) measurement using Goldmann Applanation Tonometry (GAT) after a refractive surgery is still unresolved. In this study a numerical simulation of refractive surgery and GAT is proposed as a method to evaluate accuracy of the correction formula for GAT reading after changes in corneal curvature and thickness.

Methods: In the finite element analysis the effect of the corneal shell buckling was taken into account.

Analysis of torsional eye movements using the corneal birefringence pattern.

The literature mentions several invasive methods to measure the degree of the compensatory torsional eye movement during a head-tilt. Nevertheless, none of them have yielded universally clinical tests. This study focuses on an optical system (with a circular polarizer) for noninvasive acquisition of corneal birefringence patterns (isochromes).

A Comparative Analysis of Goldmann Tonometry Correction.

Purpose: The measurement of intraocular pressure (IOP) by Goldmann applanation tonometry (GAT) is based on assumptions about corneal parameters. To correct for variations in corneal curvature and thickness, a number of equations have been proposed. This study evaluates the in vivo accuracy of these equations from individuals with primary open-angle glaucoma and compared them with measurements taken using the Pascal dynamic contour tonometer (DCT), which makes no assumptions about the corneal geometry or biomechanics.