# Exploring the implications of widespread decreases in dynamic blood flow to the retina and choroid in dry macular degeneration

> **NIH VA IK1** · IOWA CITY VA MEDICAL CENTER · 2024 · —

## Abstract

Applicant: Edward F, Linton, MD is a fellowship-trained Neuro-Ophthalmologist with a long-term goal of
becoming an independently funded translational clinician scientist, advancing sight-saving research with
expertise in multimodal imaging and functional assessment of the optic nerve and retina. An over-reaching
goal is to restore function in patients with visual loss (rehabilitation) and to intervene in patients with
progressive forms of vision loss (prevention).
Introduction: Poor blood flow has been identified as a risk factor for blindness from age-related non-exudative
macular degeneration (AMD). To save vision, research in choroidal perfusion and its normalization is needed
in AMD patients. This will be accomplished using an imaging technique that measures the dynamics of ocular
blood flow, laser speckle flowgraphy (LSFG), to complement imaging of vascular structure, using Optical
Coherence Tomography Angiography (OCT-A). This will enable the identification and monitoring of patients at
high risk of progression to advanced stages of AMD, who will be candidates for emerging interventions to
increase blood flow. Precise understanding of blood flow in AMD patients is required to capitalize on these
treatments to prevent vision loss and restore function in the millions of Americans at risk. Our preliminary data
using LSFG in the choroid and retina in a retrospective case-control study showed that ocular blood flow is
reduced in large areas even in early and intermediate AMD, which agrees with previous literature.
Methods: This proposal centers on a cross-sectional study of patients with non-exudative age-related macular
degeneration in the early, intermediate and advanced stages, as well as a cohort of control subjects stratified
by age. Blood flow will be measured in across a wide area of retina, including the macula, with laser speckle
flowgraphy, using standard techniques and a novel approach with a wide field montage image. Blood flow will
be compared between controls and patients with AMD at each stage to test the hypothesis that blood flow is
measurably reduced in all stages of dry AMD, after controlling for other risk factors. Repeat variability of blood
flow measurements will be assessed in preparation for following patients longitudinally to assess risk of
progression as a function of reduced blood flow. To test the hypothesis that blood flow reduction may precede
structural changes in the retina, we will compare the areas of reduced flow to the corresponding locations of
retina containing photoreceptors, retinal pigmented epithelium and underlying choroid. Once we have
established baseline studies of the cohort of AMD patients and age-matched control subjects in the proposed
2-year CDA-1 study, we will plan to study these subjects longitudinally in a follow-on prospective cohort study,
which the applicant will be well positioned to perform as part of a future career development proposal (CDA-2).
Career Development: Formal training wil...

## Key facts

- **NIH application ID:** 10863381
- **Project number:** 1IK1RX005029-01
- **Recipient organization:** IOWA CITY VA MEDICAL CENTER
- **Principal Investigator:** Edward F Linton
- **Activity code:** IK1 (R01, R21, SBIR, etc.)
- **Funding institute:** VA
- **Fiscal year:** 2024
- **Award amount:** —
- **Award type:** 1
- **Project period:** 2024-05-01 → 2026-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10863381

## Citation

> US National Institutes of Health, RePORTER application 10863381, Exploring the implications of widespread decreases in dynamic blood flow to the retina and choroid in dry macular degeneration (1IK1RX005029-01). Retrieved via AI Analytics 2026-05-27 from https://api.ai-analytics.org/grant/nih/10863381. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*