Related Experiment Video
Updated: May 25, 2026
10:46
Doppler Optical Coherence Tomography of Retinal Circulation
Published on: September 18, 2012
Disturbed correlation between arterial resistance and pulsatility in glaucoma patients
Luís Abegão Pinto1, Evelien Vandewalle, Ingeborg Stalmans
1Department of Ophthalmology, Centro Hospitalar de Lisboa Central, Portugal.
Acta Ophthalmologica
|January 25, 2012
Summary
Glaucoma patients exhibit altered retrobulbar blood flow dynamics, showing nonlinear relationships between resistive index and pulsatility index, unlike healthy individuals. This suggests impaired autoregulation in glaucoma, potentially linked to specific resistive index thresholds.
Area of Science:
- Ophthalmology
- Vascular Biology
- Medical Imaging
Background:
- Glaucoma is a leading cause of irreversible blindness.
- Ocular blood flow is crucial for retinal health and optic nerve function.
- Alterations in retrobulbar hemodynamics may precede or accompany glaucoma progression.
Purpose of the Study:
- To investigate alterations in pulsatility index (PI) and mean flow velocities (MFV) in glaucoma patients.
- To evaluate the significance of PI in retrobulbar autoregulation capacity in glaucoma.
Main Methods:
- Color Doppler imaging was used to measure retrobulbar vasculature in patients with primary open-angle glaucoma (POAG), normal tension glaucoma (NTG), and healthy controls.
- Kruskal-Wallis tests compared variables between groups.
- Restricted cubic splines analyzed nonlinear correlations between resistive index (RI) and PI.
Main Results:
- Mean flow velocities (MFV) were significantly lower in the short posterior ciliary arteries (SCPA) and central retinal arteries (CRA) of glaucoma patients compared to controls.
- No significant differences in resistive index (RI) or pulsatility index (PI) were found between diagnostic groups.
- Healthy individuals displayed linear correlations between RI and PI, while glaucoma patients showed nonlinear relationships in CRA and ophthalmic arteries, indicating altered autoregulation.
Conclusions:
- Glaucoma patients exhibit nonlinear relationships between RI and PI, deviating from the linear patterns seen in healthy individuals.
- These nonlinearities suggest impaired retrobulbar autoregulation in glaucoma.
- Identifying threshold RI values may help assess the relevance of autoregulatory disturbances in glaucoma.
More Related Videos
Related Concept Videos
01:25Glaucoma: Overview
Glaucoma is an eye condition characterized by increased intraocular pressure that damages the retina and optic nerve, leading to irreversible blindness if left untreated. The human eye has various components, including the cornea, iris, pupil, lens, and optic nerve. Aqueous humor is secreted by the epithelium of the ciliary body in the posterior chamber and flows through the trabecular meshwork and canal of Schlemm, maintaining normal intraocular pressure. The trabecular meshwork and the canal...
01:17Measurement of Blood Pressure
Assessing blood pressure is a standard procedure executed in virtually all medical environments. The method utilized today was established over a hundred years ago by an innovative Russian doctor, Dr. Nikolai Korotkoff. The soft ticking noise, known as Korotkoff sounds, heard while taking blood pressure readings results from turbulent blood flow within the vessels. The apparatus required for this procedure includes a sphygmomanometer, a blood pressure cuff attached to a gauge, and a stethoscope.
01:21Peripheral Arterial Disease II: Clinical Manifestations and Diagnostic Evaluation
Clinical manifestationsPeripheral Arterial Disease (PAD) manifests through a range of symptoms, from the characteristic intermittent claudication to atypical presentations and severe complications in advanced stages. Intermittent claudication, a hallmark symptom of PAD, presents as exercise-induced muscle pain that typically resolves within minutes of rest. This pain is reproducible and stems from inadequate blood flow, leading to the accumulation of lactic acid produced during anaerobic...
01:27Open Angle Glaucoma: Treatment
In open-angle glaucoma, the iridocorneal angle remains open, but the trabecular meshwork becomes stiff, slowing down the outflow of aqueous humor. This causes a buildup of aqueous humor in the anterior chamber, leading to a sudden increase in intraocular pressure. The treatment for open-angle glaucoma focuses on reducing the elevated intraocular pressure by either decreasing the secretion of aqueous humor or increasing its outflow.
Drugs such as carbonic anhydrase inhibitors, α2- and...
Drugs such as carbonic anhydrase inhibitors, α2- and...
01:16Pulse
When the heart pumps blood out, arterial elastic fibers play a crucial role in sustaining a high-pressure gradient. They expand to accommodate the received blood and then recoil - a process known as the pulse that can be either manually palpated or electronically quantified. Despite a reduction in its effect with increased distance from the heart, elements of the pulse's systolic and diastolic components persist, observable even at the arteriole level.
The pulse serves as a clinical indicator...
The pulse serves as a clinical indicator...
01:24Blood Pressure
The movement of blood in a human body, commonly referred to as blood flow, is determined by the volume of blood that traverses a certain section of the bodily system per unit time. It is the rhythmic contraction of the heart's ventricles that primarily instigates this movement. As the ventricles contract, blood is forced into the prominent arteries, which then flow from areas of greater pressure to lower pressure areas. This movement continues into smaller arteries and arterioles and...