Pilot study on the dynamic interactions between cardiac activity and corneal biomechanics during eye movements.

Background And Objective: The study examines the relationship between ocular rotations and cardiovascular functions through detailed biomechanical analysis. The study documents specific patterns of ocular movements and their synchronization with cardiovascular activity, highlighting significant correlations. These findings provide a basis for understanding the opto-biomechanical interplay between ocular and cardiovascular dynamics.

Pharmacokinetic and Pharmacodynamic Obstacles for Phage Therapy From the Perspective of Clinical Practice.

Bacteriophages present unique features that enable targeted killing of bacteria, including strains resistant to many antibiotics. However, phage pharmacokinetics and pharmacodynamics constitute much more complex and challenging aspects for researchers than those attributable to antibiotics. This is because phages are not just chemical substances, but also biological nanostructures built of different proteins and genetic material that replicate within their bacterial hosts and may induce immune responses acting as simple antigens.

Novel Method of Measuring Corneal Viscoelasticity Using the Corvis ST Tonometer.

Background: The process of rapid propagation of the corneal deformation in air puff tonometer depends not only on intraocular pressure, but also on the biomechanical properties of the cornea and anterior eye. One of the biomechanical properties of the cornea is viscoelasticity, which is the most visible in its high-speed deformations. It seems reasonable to link the corneal viscoelasticity parameter to two moments of the highest speed of corneal deformations, when the cornea buckles.

Pupil autoregulation impairment as an early marker of glaucomatous damage.

Background: Glaucoma, a degenerative and progressive disease, leads to structural and functional changes in the optic nerve head and retinal ganglion cells (RGCs), while the vasculature of the iris stays intact.

Objectives: The aim of this study was to determine whether the coherence level associated with pupil geometry and peripheral arterial pulsation can be the basis for differentiating glaucoma and glaucoma-suspected patients from a control group.

Material And Methods: This is an investigator-initiated, single-center prospective cohort study.

Corneal Buckling during Applanation and Its Effect on the Air Pressure Curve in Ocular Response Analyzer.

The paper presents, for the first time, corneal buckling, during the air puff applanation, recorded with use of Ocular Response Analyzer (ORA), when the cornea is deeper deformed after its applanation. Precise numerical analysis of the air pressure curve from the raw data, distinct local disturbances of the curve, which appear almost exactly at the time of the first and the second applanations. Thirty measurements taken on six eyes show clear dependencies between times of both applanations and appearances of local wave disturbances on the air pressure curve as well as between the amplitude of pressure wave disturbances and the respective height of applanation curve.

Data analysis of the ocular response analyzer for improved distinction and detection of glaucoma.

The purpose of this study was to evaluate the clinical utility of the output parameters of the ocular response analyzer (ORA) and those calculated from the raw ORA in subjects with healthy eyes and those with suspected glaucoma, and in patients with two types of glaucoma. The raw ORA data were analyzed using a custom software that included the Gaussian filtering of applanation curves for three different window sizes. To the best of our knowledge, these findings present a novel means of optimizing the use of measurements from the ORA, which can refine the characteristics of corneal biomechanics, enabling a distinction between the types of glaucoma and leading to an improvement in diagnosing and early detection.

Non-contact tonometry using Corvis ST: analysis of corneal vibrations and their relation with intraocular pressure.

The aim of this study was to determine characteristic frequencies of corneal vibrations occurring during air-puff intraocular pressure (IOP) measurement using the Corvis ST tonometer. Relations of frequency of the corneal vibrations with IOP were examined. Two selected vibration frequencies-frequency with maximum amplitude, and mass center of the frequency distribution area, for which the amplitude was higher than 50% (CM50)-present significant correlations with non-corrected IOP and biomechanical corrected IOP (bIOP).

Assessment of corneal and fatty tissues biomechanical response in dynamic tonometry tests by using inverse models.

Purpose: The assessment of corneal biomechanics is essential for studying ophthalmological operations, such as refractive surgeries, and for more accurate estimation of intraocular pressure. The chief aim of the current study is to characterize corneal and fatty tissues in order to construct a model to predict eye globe behavior during dynamic tonometry tests.

Methods: In the present study, images from corneal deformation, acquired from Corvis ST tonometer, were processed.

Eye retraction and rotation during Corvis ST 'air puff' intraocular pressure measurement and its quantitative analysis.

Purpose: 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.

Methods: 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.

New Approach to the Analysis of Raw Data from the Ocular Response Analyzer.

Purpose: The aim of this research was to present a new approach for the potential characteristics of the anterior eye, based on numerical analysis of the raw data from multiple measurements on 1 eye captured with use of the Ocular Response Analyzer (ORA).

Methods: The measurements were carried out 6 times on every eye, one by one, on 29 patients using the ORA. Dependencies between values of 6 applanation pressures P and P from 1 eye and the new proposed time-dependent parameters sm and smm, obtained from the raw data, were used to determine new characteristic features of the anterior eye.

Numerical analysis of corneal curvature dynamics based on Corvis tonometer images.

The paper presents numerical analysis of corneal curvature distribution, based on Corvis ST images. It was shown that a new approach to analysis of corneal curvature from tonometer images enables a better description and understanding of processes during fast corneal deformation. Ten healthy volunteers participated in nine repeated measurements on one eye.

Correlation of Oxidative and Antioxidative Processes in the Blood of Patients with Cervical Spinal Cord Injury.

The effect of cervical spinal cord injury (CSCI) on oxidative stress parameters was assessed. The study was conducted in 42 patients with CSCI (studied group), 15 patients with cerebral concussion, without CSCI (Control II), and 30 healthy volunteers (Control I). Blood was taken from the basilic vein: before and seven days after the spinal cord decompression surgery (mean time from CSCI to surgery: 8 hours) in the studied group and once in the controls.

Optical Coherence Tomography as a Tool for Ocular Dynamics Estimation.

Purpose: The aim of the study is to demonstrate that the ocular dynamics of the anterior chamber of the eye can be estimated quantitatively by means of optical coherence tomography (OCT).

Methods: A commercial high speed, high resolution optical coherence tomographer was used. The sequences of tomographic images of the iridocorneal angle of three subjects were captured and each image from the sequence was processed in MATLAB environment in order to detect and identify the contours of the cornea and iris.

Quantitative assessment of the impact of blood pulsation on images of the pupil in infrared light.

Pulsation in the blood vessels of the eye has a big impact on the dynamics of the entire eyeball and its individual elements. Blood pulsation in the retina can be recorded by the pupil, whose size is also subject to dynamic changes. The study involved synchronous measurements of pupil size using a high-speed camera, and blood pulsation using a pulse oximeter placed on the ear lobe.

Assessing subject-related variations of the Ocular Response Analyzer parameter calculation.

Background: The aim was to study the relationships between the output parameters of the Ocular Response Analyzer (ORA) and those calculated from the raw ORA data and to ascertain the subject-related variations of ORA parameter calculation procedures.

Method: Six subjects were recruited for a prospective study. Up to 32 measurements by ORA were performed in series on the dominant eye of each subject.

Measurement and analysis of the air pressure curve on the rigid lenses by use of ocular response analyzer.

Purpose: Pressure curves obtained from Ocular Response Analyzer (ORA) differ for the same patient in form and height. In some cases measurements on the subject show significant differences between recorded pressure curves. The purpose of the paper is to examine if the differences result from the corneal properties or from the device operation.

Selected parameters of the corneal deformation in the Corvis tonometer.

Introduction: Contemporary ophthalmology knows many methods of measuring intraocular pressure, namely the methods of non-contact and impression applanation tonometry. In non-contact applanation tonometers, e.g.

Phase dependencies between longitudinal corneal apex displacement and cardiovascular signals: is the ocular pulse influenced by the electrical activity of the heart?

Background: The aim was to establish phase relationships between the principal harmonic, related to the heart rate, of synchronically registered longitudinal corneal apex displacement (LCAD), blood pulsation (BP) and electrical heart activity signals in a group of healthy subjects.

Methods: Longitudinal corneal apex displacement was non-invasively measured using an ultrasonic distance sensor. Synchronously, electrocardiographic (ECG) and blood pulsation signals were acquired.

Methodology for Anti-Gene Anti-IGF-I Therapy of Malignant Tumours.

The aim of this study was to establish the criteria for methodology of cellular "anti-IGF-I" therapy of malignant tumours and particularly for glioblastoma multiforme. The treatment of primary glioblastoma patients using surgery, radiotherapy, and chemotherapy was followed by subcutaneous injection of autologous cancer cells transfected by IGF-I antisense/triple helix expression vectors. The prepared cell "vaccines" should it be in the case of glioblastomas or other tumours, have shown a change of phenotype, the absence of IGF-I protein, and expression of MHC-I and B7.

Ultrasonic in vivo measurement of ocular surface expansion.

Our aim was to ascertain whether the ultrasonic measurement of longitudinal corneal apex displacements carried out in a proper headrest is a credible method of ocular pulse (OP) detection. To distinguish between longitudinal movements of the eye globe treated as a rigid body and ocular surface expansion caused by the variations of the eye-globe volume, two ultrasound distance sensors were applied to noninvasively measure displacements of cornea and sclera. The same sensors were used to examine the influence of the anterio-posterior movements of a fixed head on the registration of corneal apex pulsation.

Antisense anti IGF-I cellular therapy of malignant tumours: immune response in cancer patients.

The treatment of cancer by antisense anti-IGF-I cellular therapy inducing immune response has evoked interest among many promising strategies. Here, we reported some results obtained from patients with cancer, mainly glioblastoma treated by this strategy, which was also extended to patients with colon carcinoma, ovary cystadenocarcinoma and prostate adenocarcinoma. It was shown that, in the phase I of clinical trial, patients vaccinated with their own tumour cells treated by antisense IGF-I presented a slight increase of temperature.

Examination of tear film smoothness on corneae after refractive surgeries using a noninvasive interferometric method.

A lateral shearing interferometer was used to examine the smoothness of the tear film. The information about the distribution and stability of the precorneal tear film is carried out by the wavefront reflected from the surface of tears and coded in interference fringes. Smooth and regular fringes indicate a smooth tear film surface.

Corneal primary aberrations compensation by oblique light incidence.

The eye is not a centered system. The line of sight connects the fovea with the center of the pupil and is usually tilted in the temporal direction. Thus, off-axis optical aberrations, mainly coma and oblique astigmatism, are introduced at the fovea.

Comparison of high-speed videokeratoscopy and ultrasound distance sensing for measuring the longitudinal corneal apex movements.

Two different methods to measure binocular longitudinal corneal apex movements were synchronously applied. High-speed videokeratoscopy at a sampling frequency of 15 Hz and a custom-designed ultrasound distance sensor at 100 Hz were used for the left and the right eye, respectively. Four healthy subjects participated in the study.

Correlation between the dioptric power, astigmatism and surface shape of the anterior and posterior corneal surfaces.

A knowledge of the shape of the cornea is of major importance for the planning and monitoring of surgery, and for the correct diagnosis of corneal diseases. Many authors have studied the geometry of the second corneal surface in the central region and it has been stated that there is a high correlation between the central radii of curvature and asphericities of the two corneal surfaces. In this work we extend this study to a larger, central, 6 mm diameter of the cornea.