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

NIH RePORTER · VA · IK1 · · view on reporter.nih.gov ↗

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
IOWA CITY VA MEDICAL CENTER
Principal Investigator
Edward F Linton
Activity code
IK1
Funding institute
VA
Fiscal year
2024
Award amount
Award type
1
Project period
2024-05-01 → 2026-04-30