Ocular blood flow biomarkers may predict long-term glaucoma progression.

Background/aim: To examine the relationship between baseline blood flow biomarkers and long-term open-angle glaucoma (OAG) progression.

Methods: 112 patients with early to moderate OAG (mean age 64.9±11.

Ocular blood flow as it relates to race and disease on glaucoma.

Glaucoma is a multifactorial progressive and degenerative optic neuropathy representing one of the world's leading cause of irreversible blindness. Currently, reduction of intraocular pressure remains the only universally approved therapy, yet a wealth of studies has identified significant vascular contributions to the disease process in certain individuals. Population-based studies have identified important racial disparities and differential risk factors in glaucoma prevalence, incidence, and progression.

Prevalence Rates and Risk Factors for Primary Open Angle Glaucoma in the Middle East.

Glaucoma is a multifactorial disease and a leading cause of irreversible blindness worldwide. Current data has demonstrated the approximate distribution of primary open-angle glaucoma (POAG) in patients of European, African, Hispanic, and Eastern Asian descent. However, a significant gap in the literature exists regarding the prevalence of POAG in Middle Eastern (ME) populations.

Topical carbonic anhydrase inhibitors and glaucoma in 2021: where do we stand?

Carbonic anhydrase inhibitors (CAIs) have been used for many decades in the treatment of glaucoma. Systemic CAIs were an early treatment option to lower intraocular pressure by reducing aqueous humour production; however, frequent side effects including polyuria and paresthesia contributed to the eventual development of topical CAIs. As topical drug development evolved over time, prostaglandin analogues and beta-blockers have become the gold standard of glaucoma therapies.

Evaluation of macular and optic nerve head parameters in amblyopic eyes: An optical coherence tomography study.

Purpose: To evaluate morphological differences in retinal nerve fibers layers (RNFL), optic nerve head (ONH), ganglion cell complex (GCC), and macular thickness between amblyopic and normal eyes from spectral domain optical coherence tomography (SD-OCT).

Methods: Of 234 eyes of 117 children, four groups emerged: group A (162 eyes of 81 non-amblyopic subjects); group B (32 fellow eyes of 32 subjects with monolateral amblyopia); group C (32 amblyopic eyes of 32 subjects affected by monolateral amblyopia); group D (8 amblyopic eyes of 4 subjects with bilateral amblyopia). Patients underwent SD-OCT for ONH parameters, RNFL, GCC and macular thickness, retina map, and ONH scan quality index (SQI).

Confocal Microscopy and Anterior Segment Optical Coherence Tomography Imaging of the Ocular Surface and Bleb Morphology in Medically and Surgically Treated Glaucoma Patients: A Review.

Glaucoma patients often suffer from ocular surface disease (OSD) caused by the chronic administration of topical anti-glaucoma medications, especially in cases of long-term therapy with preserved or multiple drugs. Additionally, glaucoma surgery may determine ocular surface changes related to the formation and location of the filtering bleb, the application of anti-mitotic agents, and the post-operative wound-healing processes within the conjunctiva. Recently, several studies have evaluated the role of advanced diagnostic imaging technologies such as in vivo confocal microscopy (IVCM) and anterior segment-optical coherence tomography (AS-OCT) in detecting microscopic and macroscopic features of glaucoma therapy-related OSD.

Physics-based modeling of Age-related Macular Degeneration-A theoretical approach to quantify retinal and choroidal contributions to macular oxygenation.

We developed a mathematical model to characterize how macular oxygenation may be affected by abnormalities in the retinal and choroidal oxygen supplies. The macular region is modeled as a layered structure including: ganglion cell and nerve fiber layers, inner plexiform layer, inner nuclear layer, outer plexiform layer, outer nuclear layer, inner segment of photoreceptors layer and retinal pigmented epithelium. Each layer is characterized by specific levels of oxygen consumption.

Structure-Function Mapping Using a Three-Dimensional Neuroretinal Rim Parameter Derived From Spectral Domain Optical Coherence Tomography Volume Scans.

Purpose: To assess the structure-function relationship in glaucoma using Humphrey visual field (HVF) perimetry and a three-dimensional neuroretinal rim parameter derived from spectral domain optical coherence tomography (SD-OCT) volume scans.

Methods: Structure-function correlation was analyzed globally and regionally (four quadrants and four sectors). Structural data included peripapillary retinal nerve fiber layer (RNFL) thickness and minimum distance band (MDB) neuroretinal rim thickness, defined as the shortest distance between the inner cup surface and the outer retinal pigment epithelium/Bruch's membrane complex.

Neurodegenerative Disorders of the Eye and of the Brain: A Perspective on Their Fluid-Dynamical Connections and the Potential of Mechanism-Driven Modeling.

Neurodegenerative disorders (NDD) such as Alzheimer's and Parkinson's diseases are significant causes of morbidity and mortality worldwide. The pathophysiology of NDD is still debated, and there is an urgent need to understand the mechanisms behind the onset and progression of these heterogenous diseases. The eye represents a unique window to the brain that can be easily assessed via non-invasive ocular imaging.

Baseline structural characteristics of the optic nerve head and retinal nerve fiber layer are associated with progressive visual field loss in patients with open-angle glaucoma.

Aims: To examine the relationship between baseline structural characteristics of the optic nerve head (ONH) and retinal nerve fiber layer (RNFL) and functional disease progression in patients with open-angle glaucoma (OAG) over 5 years.

Methods: 112 OAG patients were prospectively examined at baseline and every 6 months over a period of five years. Structural glaucomatous changes were examined with optical coherence tomography (OCT) and Heidelberg retinal tomography-III (HRT-III), and functional disease progression with automated perimetry (Humphrey visual fields).

Optic nerve head diurnal vessel density variations in glaucoma and ocular hypertension measured by optical coherence tomography angiography.

Background/aims: To evaluate diurnal variations in optic nerve head (ONH) vessel density assessed by optical coherence tomography angiography (OCT-A) in healthy subjects, ocular hypertension (OHT), and open-angle glaucoma (OAG) patients.

Methods: Forty subjects (OAG, 21; OHT, 6; healthy, 13) were assessed for vessel density percentage (VD%) and flow index in the ONH (NH VD%, NH index), and in the radial peripapillary capillary layer (RPC VD%, RPC index) at 9:00, 11:00, 14:00, 16:00, and 18:00 on a single day. Repeated measures ANOVAs were used to test for changes in the parameters measured at multiple time points.

Optic disc haemorrhage and primary open-angle glaucoma: a clinical review.

Studies have confirmed that optic disc haemorrhage (ODH) is a significant risk factor for the development and progression of primary open-angle glaucoma (POAG). Various populations have differing risk factors for developing POAG. As such, a literature review was conducted examining seven studies published in India, China, Japan, Australia, Korea and the USA.

Ocular blood flow as a clinical observation: Value, limitations and data analysis.

Alterations in ocular blood flow have been identified as important risk factors for the onset and progression of numerous diseases of the eye. In particular, several population-based and longitudinal-based studies have provided compelling evidence of hemodynamic biomarkers as independent risk factors for ocular disease throughout several different geographic regions. Despite this evidence, the relative contribution of blood flow to ocular physiology and pathology in synergy with other risk factors and comorbidities (e.

A Theoretical Approach for the Electrochemical Characterization of Ciliary Epithelium.

The ciliary epithelium (CE) is the primary site of aqueous humor (AH) production, which results from the combined action of ultrafiltration and ionic secretion. Modulation of ionic secretion is a fundamental target for drug therapy in glaucoma, and therefore it is important to identify the main factors contributing to it. As several ion transporters have been hypothesized as relevant players in CE physiology, we propose a theoretical approach to complement experimental methods in characterizing their role in the electrochemical and fluid-dynamical conditions of CE.

Evaluation of Cerebrospinal Fluid Pressure by a Formula and Its Role in the Pathogenesis of Glaucoma.

Purpose: To investigate potential associations between intraocular pressure (IOP) and cerebrospinal fluid pressure (CSFP) in patients with primary open-angle glaucoma (POAG) and healthy subjects.

Methods: Forty-three subjects were recruited. Weight and height were measured to calculate body mass index (BMI), along with blood pressure, heart rate, visual acuity, and IOP.

Review of non-invasive intracranial pressure measurement techniques for ophthalmology applications.

Assessment and monitoring of intracranial pressure (ICP) are important in the management of traumatic brain injury and other cerebral pathologies. In the eye, ICP elevation and depression both correlate with optic neuropathies, the former because of papilledema and the latter related to glaucoma. While the relationship between ICP elevation and papilledema is well established, the relationship between low ICP and glaucoma is still poorly understood.

Circadian Rhythm and Glaucoma: What do We Know?

Purpose: The current understanding of circadian regulation disorders and their involvement in glaucoma pathophysiology are poorly understood, yet they may have a substantial impact on the onset and progression of glaucoma. Herein, we review and summarize all the available literature on circadian rhythm disorder and glaucoma to uncover the impact on glaucoma risk, and we highlight future research and potential novel targets for glaucoma management.

Materials And Methods: A review of the relevant literature was performed through PubMed through August 1, 2019.

Analysis of Neuroretinal Rim by Age, Race, and Sex Using High-Density 3-Dimensional Spectral-Domain Optical Coherence Tomography.

Unlabelled: PRéCIS:: Neuroretinal rim minimum distance band (MDB) thickness is significantly lower in older subjects and African Americans compared with whites. It is similar in both sexes.

Purpose: To evaluate the relationship between age, race, and sex with the neuroretinal rim using high-density spectral-domain optical coherence tomography optic nerve volume scans of normal eyes.

Ocular changes in traumatic brain injury: A review.

Traumatic brain injury is represented by a penetrating or non-penetrating head injury, which causes disruption in the normal functioning of the brain. Traumatic brain injury has been an ardently debated topic of discussion due to its prevalence in media centric persons such as military personnel and athletes. Current assessments for traumatic brain injury have looked at vestibulo-ocular and vascular parameters to aid in diagnosis.

Vascular dysfunction in retinitis pigmentosa.

The relationship between ocular haemodynamics and retinitis pigmentosa (RP) has not been fully understood. Reductions in blood flow have been established in RP patients by a variety of studies; however, questions have yet to be answered regarding the role of vascular dysfunction in photoreceptors (PR) degeneration, the causes of vascular dysfunction in RP, as well as the diagnostic, prognostic and perhaps therapeutic potential of measuring ocular haemodynamics in RP patients. While significant evidence supports the theory that vascular dysfunction is associated with but not the cause of PR death in retinitis pigmentosa, evidence suggests that vascular abnormalities in the foveal and parafoveal regions may exacerbate cone cell loss.

Waveform parameters of retrobulbar vessels in glaucoma patients with different demographics and disease severity.

Introduction: To identify novel velocity waveform parameters of the ophthalmic artery and central retinal artery by computer-aided image processing of Doppler ultrasonography measurements, and to evaluate correlations between the waveform parameters and different demographics and disease severity of open-angle glaucoma patients.

Methods: Thirty-six images of 36 open-angle glaucoma patients were considered. A semiautomated image processing code was used to detect the digitalized ophthalmic artery and central retinal artery velocity waveforms and to extract the waveform parameters.

Lutein Complex Supplementation Increases Ocular Blood Flow Biomarkers in Healthy Subjects.

To investigate the effects of a lutein complex supplementation on ocular blood flow in healthy subjects. Sixteen healthy female patients (mean age 36.8 ± 12.

Effects of image brightness and contrast dynamic altering stimuli (DAS) when viewing video content on ocular blood flow.

Background/aim: Blood flow deficiencies of the retinal and retrobulbar circulations have been previously reported in open-angle glaucoma (OAG) and other eye diseases. Herein we investigated the effects of image brightness and contrast dynamic altering stimuli (DAS) when viewing a video content on ocular blood flow, intraocular pressure (IOP) and ocular perfusion pressure (OPP) in OAG and healthy subjects.

Methods: Thirty-five subjects, 25 with OAG (mild to moderate) and 10 healthy controls, were evaluated for blood pressure, IOP, OPP and retinal capillary blood flow before, immediately after, 30 min after and 60 min after using ReviView (a dichoptic video goggles device), which stimulates one eye with a DAS video image that is brighter and with greater contrast than the fellow eye (duration of exposure 30 min).