Boszczyk Agnieszka, Kasprzak Henryk, Jóźwik Agnieszka
Department of Optics and Photonics, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, Wrocław, Poland.
Ophthalmic Physiol Opt. 2017 May;37(3):253-262. doi: 10.1111/opo.12383.
The aim of this study was to analyse the indentation and deformation of the corneal surface, as well as eye retraction, which occur during air puff intraocular pressure (IOP) measurement.
A group of 10 subjects was examined using a non-contact Corvis ST tonometer, which records image sequences of corneas deformed by an air puff. Obtained images were processed numerically in order to extract information about corneal deformation, indentation and eyeball retraction.
The time dependency of the apex deformation/eye retraction ratio and the curve of dependency between apex indentation and eye retraction take characteristic shapes for individual subjects. It was noticed that the eye globes tend to rotate towards the nose in response to the air blast during measurement. This means that the eye globe not only displaces but also rotates during retraction. Some new parameters describing the shape of this curve are introduced. Our data show that intraocular pressure and amplitude of corneal indentation are inversely related (r = -0.83, P = 0.0029), but the correlation between intraocular pressure and amplitude of eye retraction is low and not significant (r = -0.24, P = 0.51).
The curves describing corneal behaviour during air puff tonometry were determined and show that the eye globe rotates towards the nose during measurement. In addition, eye retraction amplitudes may be related to elastic or viscoelastic properties of deeper structures in the eye or behind the eye and this should be further investigated. Many of the proposed new parameters present comparable or even higher repeatability than the standard parameters provided by the Corvis ST.
本研究旨在分析在吹气式眼压测量过程中发生的角膜表面压痕和变形以及眼球后移情况。
使用非接触式Corvis ST眼压计对一组10名受试者进行检查，该眼压计记录由吹气导致角膜变形的图像序列。对获取的图像进行数值处理，以提取有关角膜变形、压痕和眼球后移的信息。
对于个体受试者，顶点变形/眼球后移比率的时间依赖性以及顶点压痕与眼球后移之间的依赖曲线呈现出特征形状。注意到在测量过程中，眼球倾向于因气流冲击而向鼻子方向旋转。这意味着眼球在回缩过程中不仅发生位移，还会旋转。引入了一些描述该曲线形状的新参数。我们的数据表明，眼压与角膜压痕幅度呈负相关（r = -0.83，P = 0.0029），但眼压与眼球后移幅度之间的相关性较低且不显著（r = -0.24，P = 0.51）。
确定了描述吹气式眼压测量过程中角膜行为的曲线，结果表明在测量过程中眼球向鼻子方向旋转。此外，眼球后移幅度可能与眼内或眼后更深层结构的弹性或粘弹性特性有关，对此应进一步研究。许多提出的新参数比Corvis ST提供的标准参数具有相当甚至更高的可重复性。
