# Multimodal Imaging of Photoreceptor Structure in Achromatopsia

> **NIH NIH F32** · MEDICAL COLLEGE OF WISCONSIN · 2020 · $25,077

## Abstract

Project Summary
As therapeutic interventions for retinal diseases are being rapidly developed, monitoring these interventions
during clinical trials and understanding their natural history has taken on increased importance. The human
retina is easily accessible through the use of a variety of imaging tools, such as spectral domain optical
coherence tomography (SDOCT) and adaptive optics scanning light ophthalmoscopy (AOSLO). One inherited
retinal disease with future and ongoing clinical trials is achromatopsia (ACHM), which affects 1 in 30,000
people. ACHM is a congenital retinal disease associated with absent or severely reduced cone function, while
rods are thought to be unaffected. Currently, mutations in CNGA3 and CNGB3 account for approximately 70%
of ACHM case. With the implementation of a recent imaging tool, split-detector AOSLO, visualizing remnant
cone structure in the ACHM fovea is now possible. Since in ACHM cones are still present in the retina despite
not having function, ACHM would be a good model to study the hyperreflective outer retinal bands on SDOCT.
However, the rod and cone photoreceptor contribution to SDOCT signal and the symmetry of foveal cones
structure in ACHM are yet to be elucidated. These knowledge gaps represent critical barriers to the
understanding of clinical images needed for the advancement of therapeutic interventions for ACHM and other
inherited retinal diseases. Therefore, the following aims are proposed: Aim 1: Assess variability of foveal cone
structure in ACHM; Aim 2: Evaluate cone and rod contributions to SDOCT intensity as biomarkers for
photoreceptor structure. For aim 1, characterizing foveal cone structure in CNGA3- and CNGB3-associated
ACHM will utilize SDOCT to measure outer nuclear layer thickness and split-detector AOSLO to measure peak
cone density. This work should result in an improved understanding of the natural history and variability of
foveal cone structure in ACHM. The degree of remaining cone structure could aid in patient selection for future
clinical trials. For aim 2, SDOCT intensity will be measured using directional OCT and photoreceptor structure
using AOSLO. This work should result in a model to predict the intensity of bands 2 and 3 as a surrogate
marker for the degree of photoreceptor structure. These results will aid in interpretation of clinical images in
patients with a range of inherited retinal diseases. The aims proposed here are significant because they
advance our understanding of photoreceptor structure in ACHM. More broadly the methods developed here
will aid in the interpretation of clinical images of photoreceptor degeneration and therapeutic interventions, and
provide useful evidence toward the interpretation of the hyperreflective outer retinal bands on SDOCT.

## Key facts

- **NIH application ID:** 9995479
- **Project number:** 5F32EY029148-03
- **Recipient organization:** MEDICAL COLLEGE OF WISCONSIN
- **Principal Investigator:** Katie M Litts
- **Activity code:** F32 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $25,077
- **Award type:** 5
- **Project period:** 2018-09-30 → 2021-01-29

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9995479

## Citation

> US National Institutes of Health, RePORTER application 9995479, Multimodal Imaging of Photoreceptor Structure in Achromatopsia (5F32EY029148-03). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/9995479. Licensed CC0.

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