Ocular Biomechanical Responses to Long-Duration Spaceflight.

To assess the impact of microgravity exposure on ocular rigidity (OR), intraocular pressure (IOP), and ocular pulse amplitude (OPA) following long-term space missions. OR was evaluated using optical coherence tomography (OCT) and deep learning-based choroid segmentation. IOP and OPA were measured with the PASCAL Dynamic Contour Tonometer (DCT).

The Association between the Pulsatile Choroidal Volume Change and Ocular Rigidity.

Purpose: To assess the relationship between the pulsatile choroidal volume change (ΔV) and ocular rigidity (OR), an important biomechanical property of the eye.

Design: This is a prospective cross-sectional study.

Subjects: Two hundred seventeen participants (235 eyes) were included in this study.

Optic Nerve Head Pulsatile Displacement in Open-Angle Glaucoma after Intraocular Pressure Reduction Measured by Optical Coherence Tomography: A Pilot Study.

This study investigated the effect of intraocular pressure (IOP) reduction on pulsatile displacement within the optic nerve head (ONH) in primary open-angle glaucoma (POAG) patients with and without axial myopia. Forty-one POAG patients (19 without myopia, 9 with axial myopia and 13 glaucoma with no intervention) participated. Swept-source optical coherence tomography (OCT) videos of the ONH were obtained before and after IOP-lowering treatment (medical or surgical) achieving a minimum IOP drop of 3 mmHg.

Denoising OCT videos based on temporal redundancy.

The identification of eye diseases and their progression often relies on a clear visualization of the anatomy and on different metrics extracted from Optical Coherence Tomography (OCT) B-scans. However, speckle noise hinders the quality of rapid OCT imaging, hampering the extraction and reliability of biomarkers that require time series. By synchronizing the acquisition of OCT images with the timing of the cardiac pulse, we transform a low-quality OCT video into a clear version by phase-wrapping each frame to the heart pulsation and averaging frames that correspond to the same instant in the cardiac cycle.

Ocular rigidity and choroidal thickness changes in response to microgravity: A case study.

Purpose: To evaluate ocular rigidity and choroidal thickness changes in response to microgravity and the Valsalva maneuver in a private astronaut.

Methods: Ophthalmological examination and Optical Coherence Tomography were performed before, during, and after space flight. Choroidal thickness was measured at all time points at rest and during the Valsalva maneuver.

Quantification of Hypotony Maculopathy Using Spectral-Domain Optical Coherence Tomography.

Prcis: We provide a free-to-use, open-source algorithm to quantify macular hypotony based on optical coherence tomography (OCT) images. This numerical approach calculates a metric that measures the deviations of Bruch's membrane from a smooth ideal retinal layer.

Purpose: Hypotony maculopathy is a recurrent complication of glaucoma surgical interventions in which extremely low intraocular pressure triggers changes in the shape of retinal layers.

Mapping Pulsatile Optic Nerve Head Deformation Using OCT.

Objective: To develop a noninvasive technique to quantitatively assess the pulsatile deformation due to cardiac contractions of the optic nerve head (ONH).

Design: Evaluation of a diagnostic test or technology.

Participants: Healthy subjects with no history of refractive surgery, divided into 2 cohorts on the basis of their axial length (AL).

Ocular Rigidity and Current Therapy.

Ocular rigidity (OR) is an important biomechanical parameter of the eye accounting for the material and geometrical properties of the corneoscleral shell. This study used a literature search to review the role of ocular rigidity and the application of potential therapies targeting this parameter in glaucoma and myopia. Biomechanical modeling and improved understanding of the biochemistry, and molecular arrangement of sclera and its constituents have yielded important insights.

Ocular rigidity and neuroretinal damage in patients with vasospasticity: a pilot study.

Objective: Evidence suggests that ocular blood flow dysregulation in patients with vasospasticity could occur in response to biomechanical stimuli, contributing to optic nerve head susceptibility in glaucoma. We evaluate the role of vasospasticity in the association between ocular rigidity (OR) and neuroretinal damage, hypothesizing that low OR correlates with greater glaucoma damage in patients with vasospasticity.

Design: Cross-sectional study.

The Association Between Ocular Rigidity and Neuroretinal Damage in Glaucoma.

Purpose: Ocular rigidity (OR) is an important biomechanical property, thought to be relevant in the pathophysiology of open-angle glaucoma (OAG). This study aims to evaluate the relationship between OR and neuroretinal damage caused by glaucoma.

Methods: One hundred eight subjects (22 with healthy eyes, 23 with suspect discs, and 63 with OAG) were included in this study.

Correlation of ocular rigidity with intraocular pressure spike after intravitreal injection of bevacizumab in exudative retinal disease.

Background/aims: To evaluate the non-invasive measurement of ocular rigidity (OR), an important biomechanical property of the eye, as a predictor of intraocular pressure (IOP) elevation after anti-vascular endothelial growth factor (anti-VEGF) intravitreal injection (IVI).

Methods: Subjects requiring IVI of anti-VEGF for a pre-existing retinal condition were enrolled in this prospective cross-sectional study. OR was assessed in 18 eyes of 18 participants by measurement of pulsatile choroidal volume change using video-rate optical coherence tomography, and pulsatile IOP change using dynamic contour tonometry.

Non-invasive in vivo measurement of ocular rigidity: Clinical validation, repeatability and method improvement.

Ocular rigidity (OR) is thought to play a role in the pathogenesis of glaucoma, but the lack of reliable non-invasive measurements has been a major technical challenge. We recently developed a clinical method using optical coherence tomography time-lapse imaging and automated choroidal segmentation to measure the pulsatile choroidal volume change (ΔV) and calculate OR using Friedenwald's equation. Here we assess the validity and repeatability of this non-invasive technique.

Patch graft using collagen matrix (Ologen) for glaucoma drainage device exposure in a patient with Boston Keratoprosthesis type 1.

Purpose: To report the first successfully treated case of recurrent tube exposure in a patient with the Boston Keratoprosthesis type 1 with a collagen matrix patch graft (Ologen).

Observations: A 50 year-old female with a Boston Keratoprosthesis type 1 and a history of Axenfeld-Reiger syndrome presents to our department with recurrent glaucoma drainage device exposure in her left eye. After failed spontaneous closure with topical antibiotics and lubricants, she undergoes tube exposure repair using an Ologen patch graft.

Surgical Outcome of Replacing a Failed Ahmed Glaucoma Valve by a Baerveldt Glaucoma Implant in the Same Quadrant in Refractory Glaucoma.

Purpose: The purpose of this study was to describe the surgical technique and outcomes in eyes that underwent surgery to replace a failed Ahmed valve by a Baerveldt glaucoma implant in the same quadrant.

Methods: This study was a retrospective case series of 9 patients. Parameters analyzed include age, glaucoma type, prior surgery, complications, intraocular pressure (IOP), visual acuity, and number of glaucoma medications before and after the surgery.

Small-Gauge Endoscopy-Guided Pneumatic Anterior Hyaloid Detachment: A New Surgical Technique for Combined Pars Plana Vitrectomy and Pars Plana Glaucoma Drainage Implant.

Background And Objective: Pars plana glaucoma drainage implant (GDI) occlusion is mainly related to entrapment of residual anterior vitreous gel in the implant. The aim of the present report is to describe a new surgical technique to induce pneumatic anterior hyaloid detachment in eyes with GDI.

Patients And Methods: This is a description of the surgical technique used to induce pneumatic anterior hyaloid detachment.

Pilot study of the pulsatile neuro-peripapillary retinal deformation in glaucoma and its relationship with glaucoma risk factors.

Purpose: To perform a pilot study of the neuro-peripapillary retinal tissue deformation during the cardiac cycle among healthy eyes, ocular hypertensive (OHT), open angle glaucoma suspect (OAG-S), and early open angle glaucoma (EOAG) patients using video rate optical coherence tomography (OCT) image series.

Methods: OCT line scan sequences of the same region of the optic nerve head (ONH) were obtained from 15 EOAG, 6 OHT, 10 OAG-S, and 10 healthy age-matched eyes. One eye per patient was studied.

Maladaptive coping strategies and glaucoma progression.

The identification of modifiable risk factors for glaucoma progression is needed. Our objective was to determine whether maladaptive coping styles are associated with recent glaucoma progression or worse visual field mean deviation.A hospital-based case-control study was conducted in the Glaucoma Service of Maisonneuve-Rosemont Hospital in Montreal, Canada.

Neuroretinal Rim Area Change in Glaucoma Patients With Visual Field Progression Endpoints and Intraocular Pressure Reduction. The Canadian Glaucoma Study: 4.

Purpose: To compare rim area rates in patients with and without the visual field (VF) progression endpoint in the Canadian Glaucoma Study and determine whether intraocular pressure (IOP) reduction following the endpoint altered rim area rate.

Design: Prospective multicenter cohort study.

Methods: setting: University hospitals.

Impact of a Brief Educational Intervention on Glaucoma Persistence: A Randomized Controlled Clinical Trial.

Purpose: To determine whether two sessions of a glaucoma educational intervention resulted in better persistence to glaucoma eye drop therapy compared to normal care.

Methods: A total of 165 patients newly diagnosed with glaucoma who required eye drop therapy were recruited into a randomized clinical trial from the glaucoma clinic at Maisonneuve-Rosemont Hospital in Montreal, Canada. Patients were randomized to either an immediate intervention or normal care.

Automatic segmentation of the optic nerve head for deformation measurements in video rate optical coherence tomography.

Optical coherence tomography (OCT) imaging has become a standard diagnostic tool in ophthalmology, providing essential information associated with various eye diseases. In order to investigate the dynamics of the ocular fundus, we present a simple and accurate automated algorithm to segment the inner limiting membrane in video-rate optic nerve head spectral domain (SD) OCT images. The method is based on morphological operations including a two-step contrast enhancement technique, proving to be very robust when dealing with low signal-to-noise ratio images and pathological eyes.

Gonioscopic findings associated with a positive dark-room provocative test in narrow angles after laser iridotomy.

Purpose: To determine clinical factors and ultrasound biomicroscopic (UBM) findings associated with a positive prone dark-room provocative test (DRPT) in patients with narrow angles after laser peripheral iridotomy (LPI).

Patients And Methods: Seventeen eyes with a positive DRPT and 18 eyes with a negative DRPT were included in this comparative case series, based on chart review of patients diagnosed with narrow angles persisting after LPI who had undergone clinical evaluation with a 45-minute DRPT and UBM imaging. Subjects with a positive DRPT [an increase of intraocular pressure (IOP) of 6 mm Hg or more] were compared with a negative DRPT control group.

Transplantation of mesenchymal stem cells promotes tissue regeneration in a glaucoma model through laser-induced paracrine factor secretion and progenitor cell recruitment.

Among bone marrow cells, hematopoietic and mesenchymal components can contribute to repair damaged organs. Such cells are usually used in acute diseases but few options are available for the treatment of chronic disorders. In this study, we have used a laser-induced model of open angle glaucoma (OAG) to evaluate the potential of bone marrow cell populations and the mechanisms involved in tissue repair.

The heritability of glaucoma-related traits corneal hysteresis, central corneal thickness, intraocular pressure, and choroidal blood flow pulsatility.

Purpose: The purpose of this work was to investigate the heritability of potential glaucoma endophenotypes. We estimated for the first time the heritability of the pulsatility of choroidal blood flow. We also sought to confirm the heritability of corneal hysteresis, central corneal thickness, and 3 ways of measuring intraocular pressure.

Analysis of pulsatile retinal movements by spectral-domain low-coherence interferometry: influence of age and glaucoma on the pulse wave.

Recent studies have shown that ocular hemodynamics and eye tissue biomechanical properties play an important role in the pathophysiology of glaucoma. Nevertheless, better, non-invasive methods to assess these characteristics in vivo are essential for a thorough understanding of degenerative mechanisms. Here, we propose to measure ocular tissue movements induced by cardiac pulsations and study the ocular pulse waveform as an indicator of tissue compliance.