# Development of a supercontinuum laser source interferometer with sub-micron resolution to understand tear film structure and function in dry eye disease

> **NIH NIH R21** · UNIVERSITY OF ALABAMA AT BIRMINGHAM · 2022 · $105,881

## Abstract

Project Summary
 In humans, the precorneal tear film (PCTF) is a thin layer (~3-5 µm) of a complex biological fluid coating the
ocular surface, that serves to nourish and protect the ocular surface and provide a smooth refractive optical
surface for vision. In dry eye disease, the PCTF becomes thinner, and destabilizes (evaporates) rapidly leading
to hyperosmolarity, inflammation, and ocular surface desiccation. More than 30 million people in the United
States are impacted by dry eye disease and the economic burden to society is estimated to be over $50 billion.
Dry eye disease continues to be a challenge to diagnose, monitor, and treat because as many dry eye tests are
conducted inconsistently, lack sufficient reliability or accuracy, and do not correlate with symptoms of the
disease. Clinical measures of tear film dynamics (thinning and breakup) are subjective in nature and generally
lack validity and repeatability. Therefore, novel, non-invasive optical measures that are highly reliable and
accurate are needed to better diagnose the disease, in addition to monitor the impact of treatments.
 In prior work, we published a mathematical model to systematically analyze the light reflected back from the
cornea surface. With this model, the thickness of the PCTF is insensitive to the noise arising from the cornea or
light source. The model was validated using a fiber-based interferometry system. The main drawback of that
interferometry system is that it is spatially limited to a single point at the apex of the cornea (~30 µm). Although
our other previous studies revealed that the distribution of PCTF varied over the ocular surface, and the
characterization of these attributes in a large fieldview will provide critical information to diagnose and monitor
dry eye disease, the current system was limited to a single point due to the poor focusing property of the thermal
light source. A supercontinuum (SC) light source can upgrade the current system to a point-scanning system.
Furthermore, the proposed SC interferometer will enable a wide field view of the PCTF by a customized objective
lens. The lens will be developed based on our previous investigation, with a focal field specifically designed for
imaging over the cornea surface. This innovative interferometer will achieve unprecedented thickness sensitivity
(~0.33 µm) of the tear film across the human cornea. Aim 1 is to construct a supercontinuum light source
interferometer with a high resolution (~0.33 µm), and a wide field-of-view. In Aim 2, test and validate the new
system by examining in vitro agreement and variance with flat thickness standards and curved glass model eyes.
Aim 3 will apply the new system to characterize the PCTF of human subjects with and without dry eye disease.
 The long-term impact of this research will improve our understanding of the mechanisms driving tear film
dynamics to better understand mechanisms of disease or to development novel treatments that address
mechanisms of ...

## Key facts

- **NIH application ID:** 10459532
- **Project number:** 5R21EY033029-02
- **Recipient organization:** UNIVERSITY OF ALABAMA AT BIRMINGHAM
- **Principal Investigator:** Yuqiang Bai
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $105,881
- **Award type:** 5
- **Project period:** 2021-08-01 → 2023-10-22

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10459532

## Citation

> US National Institutes of Health, RePORTER application 10459532, Development of a supercontinuum laser source interferometer with sub-micron resolution to understand tear film structure and function in dry eye disease (5R21EY033029-02). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10459532. Licensed CC0.

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