Direct Measures of Retinal Blood Flow and Autoregulation as Robust Biomarkers for Early Glaucoma

University of Maryland, Baltimore

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.

Description

There is strong evidence for a vascular component in the development and progression of primary open angle glaucoma (POAG). Specifically, glaucoma is associated with impaired retinal blood flow (RBF) and autoregulation of RBF. Autoregulatory impairment may precede retinal ganglion cell (RGC) loss and has been proposed as a potentially early, reversible biomarker. The rationale underlying this proposal is that highly precise and accurate, direct measures of RBF are necessary to study dynamic changes in RBF and their effect on RGCs. Current methods of quantifying RBF remain limited as the majori…

Eligibility

Age range: 18–88 years
Sex: All
Healthy volunteers: Yes

Detailed criteria

Inclusion Criteria: 1. age over 18 years 2. open angle in gonioscopy (grade 3 or 4 in Shaffer classification) 3. 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: 1\) 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…

Interventions

Diagnostic Test
Indocyanine Green Angiography
Erythrocyte Mediated Angiography with indocyanine green as well as conventional indocyanine green angiography will be conducted to determine retinal blood flow
Biological
Isocapnic Oxygen
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.
Diagnostic Test
Ocular Imaging with Optical Coherence Tomography (OCT) and Adaptive Optics (AO)
Investigators will image subjects with OCT as well as AO technology to determine retinal ganglion cell density, vessel density, and vessel flowrates

Locations (4)

University of Maryland Faculty Physicians, Inc
Baltimore, Maryland
University of Maryland Medical Center
Baltimore, Maryland
University of Maryland, Baltimore
Baltimore, Maryland
Food and Drug Administration (FDA)
Silver Spring, Maryland