# Ocular Growth, Emmetropia, and Interphotoreceptor Retinoid-Binding Protein (IRBP)

> **NIH NIH R01** · EMORY UNIVERSITY · 2020 · $436,802

## Abstract

SUMMARY
IRBP is expressed much earlier than needed for any putative role in the visual cycle. In the previous grant
cycle, we showed that IRBP is needed in early retina development, as without it we detected morphological
changes coincident with terminal differentiation of rods and cones, and precocious development of the outer
plexiform layer.
At the same time, we discovered excessive eye growth and elongation of the optical axis starting distinctly at
P7. This implies a role for IRBP in controlling eye growth even without vision-based signaling.
We now know that IRBP loss causes diverse and severe eye diseases including profound myopia and retinal
degeneration, and we recently discovered sluggish pupillary light reflexes (PLRs).
In recent human GWAS studies, IRBP polymorphisms are associated with refractive error and corneal
curvature. Previous linkage studies established that IRBP defects caused combined RP and severe myopia.
We view abnormalities of IRBP deficiency in the context of eye disease that affect normal determination of eye
size, based on strong and abundant previous and concurrent work in developmental biology of the Drosophila
eye and organ size fate. We test the same five principal pathways that regulate size determination in the IRBP
knockout eye.
We seek to understand posited hierarchical relationships among myopia, RD, and other abnormalities in IRBP
mutations. To do that we have constructed and validated a new conditional knockout (KO) mouse and a new
traditional KO. Here we use them to sort out the temporal, spatial, and mechanistic relationships that cause
these three major symptoms. Last, we test efficacy of drugs known to slow myopia or organ size, in the IRBP-/-
model asking if they are effective in reducing any or all IRBP deficiency symptoms.

## Key facts

- **NIH application ID:** 9968243
- **Project number:** 5R01EY021592-07
- **Recipient organization:** EMORY UNIVERSITY
- **Principal Investigator:** JEFFREY H BOATRIGHT
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $436,802
- **Award type:** 5
- **Project period:** 2013-06-01 → 2022-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9968243

## Citation

> US National Institutes of Health, RePORTER application 9968243, Ocular Growth, Emmetropia, and Interphotoreceptor Retinoid-Binding Protein (IRBP) (5R01EY021592-07). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9968243. Licensed CC0.

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