Retinal Blood Flow and Autoregulation

NCT05344274 | Recruiting Phase 4 DMC FDA Drug FDA Device

• 1 other identifier: HP-00055126
• Study Type: interventional
• Target: 90
• Locations: 1 country
• Sites: 4

Brief Summary

The purpose of this study is to establish autoregulation of retinal blood flow in arterioles and capillaries as a biomarker for early primary open angle glaucoma.

Conditions

Glaucoma

Keywords

glaucoma; retinal blood flow; erythrocyte mediated angiography; adaptive optics

Outcome Measures

Primary Outcomes (1)

• Autoregulation of retinal blood flow

  Autoregulation of flow is measured by the percent flow difference in flow between air and oxygen

  3 years

Study Arms (1)

Isocapnic Oxygen

EXPERIMENTAL

Investigators will evaluate retinal blood flow in response to oxygen supplementation.

Diagnostic Test: Indocyanine Green Angiography; Biological: Isocapnic Oxygen; Diagnostic Test: Ocular Imaging with Optical Coherence Tomography (OCT) and Adaptive Optics (AO)

Interventions

Indocyanine Green Angiography DIAGNOSTIC_TEST

Erythrocyte Mediated Angiography with indocyanine green as well as conventional indocyanine green angiography will be conducted to determine retinal blood flow

Isocapnic Oxygen

Isocapnic Oxygen BIOLOGICAL

Investigators will evaluate retinal blood flow (RBF) in response to oxygen supplementation at a constant level of carbon dioxide (isocapnic hyperoxia) to isolate the vascular autoregulatory response to oxygen.

Isocapnic Oxygen

Ocular Imaging with Optical Coherence Tomography (OCT) and Adaptive Optics (AO) DIAGNOSTIC_TEST

Investigators will image subjects with OCT as well as AO technology to determine retinal ganglion cell density, vessel density, and vessel flowrates

Isocapnic Oxygen

Eligibility Criteria

• Age: 18 Years - 88 Years
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• age over 18 years
• open angle in gonioscopy (grade 3 or 4 in Shaffer classification)
• refractive error within the range of +3.00 to -8.00 diopters (4) best-corrected visual acuity 20/25 or better (5) Individuals recruited will be in one of the 3 groups:
• \) Early Glaucoma as per Hodapp-Anderson-Parrish Criteria (54). Early glaucoma subjects specifically with visual field defects restricted to one side of the horizontal midline will be selected to allow for comparison of rates of progression in both hemifields. Individuals will need to be off of glaucoma medications for four weeks to participate in the study. 2) Pre-perimetric glaucoma defined as the presence of glaucomatous optic nerve damage (e.g., focal notching, rim thinning), RNFL defect, and the absence of a definite glaucomatous visual field defect using standard automated perimetry at the three most recent consecutive examinations. A glaucomatous visual field defect is defined as either 3 or more abnormal points with a P\<0.05, of which at least 1 point has a pattern standard deviation (PSD) of P\<0.01; or a PSD of P\<0.05; or glaucoma hemifield test values outside the normal limits. (55,56) 3) Control group - A subject with no family history of glaucoma who has the following: a) OCT with all four quadrants within the normal range for age-matched controls, b) reliable visual fields with glaucoma hemifield test within normal limits and determined to be normal by a glaucoma specialist, and c) cup-to-disc ratio of 0.4 or lower and asymmetry of the cup to disc ratio no greater than 0.1 as determined by a glaucoma specialist.
• Control subjects will be age matched to the early glaucoma subjects.

You may not qualify if:

• corneal abnormalities or other conditions preventing reliable applanation tonometry
• retinal disease affecting retinal nerve fiber layer thickness such as vitreomacular traction as determined by a glaucoma specialist
• secondary glaucoma
• history of prior ocular surgery other than uncomplicated cataract surgery or laser trabeculoplasty
• inability to safely be off of glaucoma medications for 4 weeks
• inability to obtain OCT angiography data due to excessive eye motion or inability to fixate
• unreliable visual fields
• any history of smoking in the past 6 months
• cataract greater than lens opacity classification system (LOCS) II Grade≥2
• diagnosis of diabetes, hypertension, or other known vascular disorder such as vasculitis

Sponsors & Collaborators

• University of Maryland, Baltimore: lead

Study Sites (4)

University of Maryland Faculty Physicians, Inc

Baltimore, Maryland, 21201, United States

RECRUITING

University of Maryland Medical Center

Baltimore, Maryland, 21201, United States

RECRUITING

University of Maryland, Baltimore

Baltimore, Maryland, 21201, United States

RECRUITING

Food and Drug Administration (FDA)

Silver Spring, Maryland, 20903, United States

RECRUITING

MeSH Terms

Conditions

Glaucoma

Interventions

Tomography, Optical Coherence

Condition Hierarchy (Ancestors)

Ocular Hypertension; Eye Diseases

Intervention Hierarchy (Ancestors)

Tomography, Optical; Optical Imaging; Diagnostic Imaging; Diagnostic Techniques and Procedures; Diagnosis; Tomography; Investigative Techniques

Central Study Contacts

Osamah Saeedi, MD, MS

CONTACT

(410) 328-5929; osaeedi@som.umaryland.edu

Study Design

• Study Type: interventional
• Phase: phase 4
• Allocation: NA
• Masking: NONE
• Purpose: DIAGNOSTIC
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Associate Professor

Study Record Dates

• First Submitted: April 18, 2022
• First Posted: April 25, 2022
• Study Start: May 23, 2022
• Primary Completion (Estimated): September 1, 2027
• Study Completion (Estimated): September 1, 2027
• Last Updated: December 2, 2025

Record last verified: 2025-11

Locations

US (4)