# Contact Lens Wear, Bacteria, and Corneal Homeostasis

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA BERKELEY · 2020 · $392,500

## Abstract

Summary:
Worn by >40 million people in the USA alone, contact lenses are associated with a risk of sight-threatening
infection. With increasing use for myopia prevention and efforts to develop lenses for technological purposes, a
surge in lens usage (extended wear specifically) is predicted. Unfortunately, research related to lens-related
complications has been hindered by lack of an in vivo model amenable to the many research tools available
only for mice. Following a 25-year effort, we have developed a mouse contact lens wear model. This utilizes
silicone hydrogel lenses custom made by a contact lens manufacturer to fit mouse eyes, and does not require lid
suturing. The lenses enable corneal infection when contaminated with P. aeruginosa, the most common
causative agent of contact lens-related keratitis in people.
Foundational to understanding contact lens related infection is knowing how a lens impacts the cornea without
bacterial inoculation. Preliminary data show the mouse model replicates multiple events occurring during
human lens wear, including colonization of the lens with commensal-type bacteria, and a dendritic cell (DC)
response within 24 h. Moving beyond what is feasible using human subjects, high resolution time-lapse
imaging of mice with fluorescent cell membranes revealed normally not present motile cells resembling
neutrophils in the stroma after 6 days of wear. Immunohistochemistry confirmed infiltration of Ly6G+ cells
(neutrophil marker). This DC/Ly6G+ response without pathology fits the definition of parainflammation as “a
low-grade inflammatory response at an intermediate state between tissue homeostasis and classic
inflammation which can be induced by persistent tissue stress…”
The three aims of this project will explore; 1) triggers of parainflammation during contact lens wear, 2) how the
signal is transduced within the cornea to drive the Ly6G+ cell response, and 3) its significance during microbe
challenge. The hypothesis, based on published and preliminary data, is that parainflammation during contact
lens wear in mice can be triggered by microbes colonizing the lens, initiating a sequence of events not otherwise
occurring in the normally microbiome-free cornea that function to protect it against commensal-type bacteria,
but which primes the cornea to respond overly-aggressively to P. aeruginosa.
!

## Key facts

- **NIH application ID:** 9920709
- **Project number:** 5R01EY030350-02
- **Recipient organization:** UNIVERSITY OF CALIFORNIA BERKELEY
- **Principal Investigator:** Suzanne MJ FLEISZIG
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $392,500
- **Award type:** 5
- **Project period:** 2019-05-01 → 2024-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9920709

## Citation

> US National Institutes of Health, RePORTER application 9920709, Contact Lens Wear, Bacteria, and Corneal Homeostasis (5R01EY030350-02). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9920709. Licensed CC0.

---

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