Corneal Vibrations during Intraocular Pressure Measurement with an Air-Puff Method

Abstract

Introduction The paper presents a commentary on the method of analysis of corneal vibrations occurring during eye pressure measurements with air-puff tonometers, for example, Corvis. The presented definition and measurement method allow for the analysis of image sequences of eye responses—cornea deformation. In particular, the outer corneal contour and sclera fragments are analysed, and 3D reconstruction is performed. Methods On this basis, well-known parameters such as eyeball reaction or corneal response are determined. The next steps of analysis allow for automatic and reproducible separation of four different corneal vibrations. These vibrations are associated with (1) the location of the maximum of cornea deformation; (2) the cutoff area measured in relation to the cornea in a steady state; (3) the maximum of peaks occurring between applanations; and (4) the other characteristic points of the corneal contour. Results The results obtained enable (1) automatic determination of the amplitude of vibrations; (2) determination of the frequency of vibrations; and (3) determination of the correlation between the selected types of vibrations. Conclusions These are diagnostic features that can be directly applied clinically for new and archived data.

A pilot study for intraocular pressure measurements based on vibroacoustic parameters

“…An ideal tonometer yields accurate, reproducible, and repeatable measurements without influencing the IOP or injuring the eye. At present, different models of noncontact tonometer, Goldmann applanation tonometer (GAT), rebound tonometer, and Tono-Pen are being used in clinical practice 4 – 10 . Among various tonometers, the GAT is the most commonly used type of tonometer and regarded as the reference standard.…”

Analysis of Corneal Distortion after Myopic PRK

“…Assessment of in vivo corneal biomechanical properties (CBP) is gaining more importance in many aspects of ophthalmology, such as refractive surgery [ 1 ], corneal transplant [ 2 , 3 ], intraocular pressure evaluation [ 4 ] and overall eyeball deformation analysis [ 5 ]. There are currently two devices able to provide CBP evaluation, and both of them analyze the corneal response to an air pulse stimulus: the Ocular Response Analyzer (ORA; Reichert Ophthalmic Instruments, Buffalo, NY, USA) [ 6 ] and the Corvis ST (CST; Oculus, Wetzlar, Germany) [ 7 , 8 ].…”

Remote and low-cost intraocular pressure monitoring by deep learning of speckle patterns

“…17 Even though such procedures employ sound-driven technology to measure the physical properties of the eyes, no association with IOP has been found. 10,18 An alternative method of IOP measurement is based on the air puff tonometer, which evaluates IOP based on the resistance of the eye to the air puff. 19 However, for several reasons, the method is not suitable for obtaining full IOP profiles over long periods.…”