# High Resolution Functional Imaging of the Retina

> **NIH NIH R01** · UNIVERSITY OF ROCHESTER · 2022 · $484,146

## Abstract

Project Summary
Non-invasive methodologies to visualize individual cells and assess molecular dynamics are needed
to improve our understanding of visual function and cellular metabolism in the living eye. Some of the
key molecules involved in the visual cycle and cellular energy production are intrinsically fluorescent.
However, they are inaccessible in the living eye using single-photon excitation because the excitation
wavelength range is not transmitted by the optics of the eye. We have developed two-photon excited
fluorescence ophthalmoscopy (TPEFO) to excite these otherwise inaccessible fluorophores with near-
infrared light in conjunction with an adaptive optics scanning light ophthalmoscope that enables non-
invasive high-resolution imaging of many different cell classes throughout the in vivo retina. With
TPEFO, visual cycle kinetics can be characterized through the intensity changes of emitted two-photon
excited fluorescence from photoreceptors. During this funding period, the unique capabilities of TPEFO
will be enhanced to measure additional meaningful fluorescence properties in pre-clinical models. As
a window into the molecular dynamics of the visual cycle, we will track, in conjunction with the kinetics
of emitted fluorescence in response to visual stimulation, changes in the fluorescence lifetime of
photoreceptors. Our second aim is to non-invasively measure neuronal function by tracking emitted
two-photon excited fluorescence kinetics and lifetime from the inner retina. Finally, we will compare the
TPEFO intensity emitted in different spectral bands to calculate the optical redox ratio, a measure of a
cell's balance between aerobic and anaerobic metabolism. All of these measures may be indicators of
cell health and function. In addition to characterizing the TPEFO properties in healthy eyes, we will use
systemic hypoxia as a model of altered cellular respiration to represent the potential changes that occur
early in disease. This research has the potential to provide insight into normal and altered biochemical
processes and improve our understanding of diseases that impact retinal metabolism and visual
function such as glaucoma, macular degeneration and Leber hereditary optic neuropathy.

## Key facts

- **NIH application ID:** 10372537
- **Project number:** 2R01EY022371-09A1
- **Recipient organization:** UNIVERSITY OF ROCHESTER
- **Principal Investigator:** Jennifer J Hunter
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $484,146
- **Award type:** 2
- **Project period:** 2012-04-01 → 2023-06-01

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10372537

## Citation

> US National Institutes of Health, RePORTER application 10372537, High Resolution Functional Imaging of the Retina (2R01EY022371-09A1). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10372537. Licensed CC0.

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