# Ocular hemodynamics of rat model of glaucoma

> **NIH NIH R01** · COLUMBIA UNIVERSITY HEALTH SCIENCES · 2021 · $434,689

## Abstract

Glaucoma is one of the primary causes of irreversible vision loss in this country and worldwide. It is a multi-
factorial disease, or family of diseases, characterized by death of retinal ganglion cells (RGCs) and optic
neuropathy. It has long been known that age, elevated intraocular pressure (IOP) and family history are
glaucoma risk factors. It is now appreciated that reduced ocular perfusion also represents a significant risk factor.
At present, all medical and surgical approaches to glaucoma management focus on control of IOP. Potentially,
correction of impaired ocular perfusion might be a fruitful approach in conjunction with conventional
management, but to make progress in exploiting this factor means for evaluating flow in small animal models of
glaucoma will be crucial.
We developed ultrafast compound plane-wave ultrasound technology for visualization and measurement of flow
in the orbital vessels, choroid and anterior segment of the normal and glaucomatous human eye. There are many
advantages, however, in applying this technique to animal models of glaucoma, where controlled experimental
conditions and histologic evaluation can be utilized. The level of resolution provided by the plane-wave
technique, however, is inadequate for small rodent models. In the proposed study, we will use the recently
developed technique of super-resolution imaging (SRI) to address this shortcoming. SRI is based on tracking of
contrast microbubbles which are much smaller than a wavelength as they move through the microvasculature.
SRI, in combination with ultrafast plane wave imaging, will be used to image blood-flow in the orbital arteries,
choroid and anterior segment of the rat eye at non-diffraction limited, sub-wavelength resolution. We will
characterize flow after acute elevation of IOP by anterior chamber cannulation, by chronic IOP elevation induced
by impairment of aqueous outflow produced by injection of hypertonic saline into the episcleral veins, and with
optic nerve ischemia induced by laser photocoagulation of vessels at the optic nerve head. We will determine
the effect of these interventions on ocular blood flow in the major vessels supplying the eye, the choroid and
anterior segment simultaneously. Time-lags between arterial and choroidal flow will be considered as an
indicator of uveal compliance, which may be altered in glaucoma. Measures of cumulative IOP and blood flow
impairment will be correlated with RGC and optic nerve damage determined histologically. We will also treat
ocular hypertensive rats with betaxolol, to lower IOP, and with astaxanthin, to enhance choroidal flow, and
measure and compare their effects on IOP, flow and tissue damage.
The proposed research will demonstrate a new technique for characterization of orbital and uveal flow, enabling
use of preclinical models for exploring the effect of improved ocular perfusion on glaucomatous neuropathy.

## Key facts

- **NIH application ID:** 10164790
- **Project number:** 5R01EY028550-04
- **Recipient organization:** COLUMBIA UNIVERSITY HEALTH SCIENCES
- **Principal Investigator:** Ronald H Silverman
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $434,689
- **Award type:** 5
- **Project period:** 2018-05-01 → 2023-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10164790

## Citation

> US National Institutes of Health, RePORTER application 10164790, Ocular hemodynamics of rat model of glaucoma (5R01EY028550-04). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10164790. Licensed CC0.

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