# Anatomical and functional imaging of the conventional outflow pathway

> **NIH NIH F30** · NORTHWESTERN UNIVERSITY · 2024 · $53,974

## Abstract

Project Summary: Glaucoma is the leading cause of irreversible blindness worldwide. Currently, the only
effective treatment for glaucoma is intraocular pressure (IOP) reduction. Physiologically, IOP is regulated by the
aqueous outflow from the anterior chamber of the eye, with the vast majority leaving through the conventional
outflow pathway. Despite the importance of the conventional outflow pathway, essential questions such as the
relative contribution of the distal pathway to outflow resistance and the factors predisposing regions of the outflow
pathway to be high and low flow remain unknown. Emerging imaging modalities such as optical coherence
tomography, mainly used for retinal imaging, can provide anatomical and functional information that will elucidate
the physiological behavior of the outflow pathway in vivo. Recent evidence using aqueous angiography shows
that flow patterns in the outflow pathway can be used to increase the effectiveness of minimally invasive
glaucoma surgery (MIGS). The PI is an MD/PhD trainee who proposes to utilize the ultrahigh (~1.3 microns in
tissue) axial resolution of visible-light optical coherence tomography (vis-OCT) to noninvasively assess the
physiology of the conventional outflow pathway in vivo. Using the information acquired for OCT, the goal is to
develop noninvasive methods to assess regional flow patterns and improve MIGS. Vis-OCT is capable of
generating three-dimensional volumetric information consisting of both anatomical and functional data.
Additionally, the shorter wavelengths of light used by vis-OCT increase its axial resolution and provides
increased sensitivity to slower blood flow and motion. Since increased resistance in any portion of the outflow
pathway influences outflow, the high resolution of vis-OCT will be used to generate quantitative anatomical and
functional measurements for all parts of the outflow pathway (trabecular meshwork, Schlemm’s canal, and distal
vasculature). Thus, it is hypothesized that anatomical and functional information generated from imaging the
outflow pathway in rodents can serve as biomarkers for understanding the flow patterns within the outflow
pattern. To investigate this hypothesis, the PI proposes two aims: Aim 1 utilizes vis-OCT for anatomical imaging,
measuring Schlemm canal volume and distal vasculature structure to make predictions to discover structural-
function correlates related to regional outflow. Aim 2 focuses on the development of functional metrics, including
the response of the pathway to pharmacological interventions and motion of the trabecular meshwork in
response to intraocular pressure changes, to predict regional outflow. The training environment is well suited for
this investigation, with the mentors' labs being experts in designing OCT systems and the co-mentors lab being
experts in imaging aqueous outflow. This research leverages a diverse group of mentors with expertise in
biophotonics, physiology, biomedical engineering, and cl...

## Key facts

- **NIH application ID:** 11005695
- **Project number:** 5F30EY034033-02
- **Recipient organization:** NORTHWESTERN UNIVERSITY
- **Principal Investigator:** Raymond Fang
- **Activity code:** F30 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $53,974
- **Award type:** 5
- **Project period:** 2023-09-01 → 2025-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/11005695

## Citation

> US National Institutes of Health, RePORTER application 11005695, Anatomical and functional imaging of the conventional outflow pathway (5F30EY034033-02). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/11005695. Licensed CC0.

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