# Changes in corneal mechanics due to glycosaminoglycan depletion and corneal cross-linking therapy

> **NIH NIH R21** · UNIVERSITY OF ILLINOIS AT CHICAGO · 2020 · $194,721

## Abstract

Project Summary
The uncorrected refractive error is the most common cause of impaired vision throughout the world. The
cornea and the lens, the main refractive elements of the eye, work in tandem to focus the incoming light on
the retina; refractive errors occur when either the cornea or the lens fails to function properly. It is estimated
that refractive errors affect about 150 million Americans who spend over $15 billion each year on eyewear.
According to National Health and Nutrition Examination Survey results, over one hundred and ten million
Americans could achieve normal vision with refractive correction. Corneal ectasia may happen after
refractive surgical procedures such as LASIK and PRK. In addition to corneal ectasia after LASIK,
progressive keratoconus affects one in every 2000 Americans and is still an indication for corneal
transplant. The progressive nature of this disease significantly affects the mental health and quality of life of
patients. In other words, the public health impact of keratoconus is disproportionate to its relatively low
prevalence because it primarily affects very young adults. Corneal cross-linking (CXL) treatment is a
relatively safe and efficient method to slow down or completely arrest the progression of keratoconus. It has
also been used to stabilize and even improve the visual acuity in patients prone to develop ectasia after
LASIK. Nevertheless, even after years of research, precise mechanisms underlying this treatment
procedure are not fully understood. Keratoconus is associated with the disruption of the collagen fibrils,
decreased proteoglycan content, and a significant reduction in corneal biomechanical strength. A clear
understanding of the mechanisms that confer elasticity to corneal extracellular matrix provides the
necessary information for improvement of the standard CXL procedure and even development of new
therapeutic intervention in the diseased states. In this R21-level research study, the PI proposes to
investigate the interrelation between CXL therapy and ultrastructure of corneal extracellular matrix. This
project characterizes the structural roles of the collagen fibrils, glycosaminoglycans, and collagen fibril–
glycosaminoglycan interactions. To this end, the changes in mechanical response of corneal samples
following glycosaminoglycan degradation and corneal cross-linking will be measured. The proposed
research is innovative because it will devise a novel and unique framework for rigorous investigation of the
stiffening effects of the corneal cross-linking therapy. After completing this R21 study and quantifying
possible structural roles of collagen fibrils microstructure and glycosaminoglycan composition in
effectiveness of the CXL treatment, we will pursue R01 level funding in order to extend our research
program and further investigate the biomechanics of corneal tissue in injury and disease.

## Key facts

- **NIH application ID:** 9913545
- **Project number:** 5R21EY030264-02
- **Recipient organization:** UNIVERSITY OF ILLINOIS AT CHICAGO
- **Principal Investigator:** Hamed Hatami-Marbini
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $194,721
- **Award type:** 5
- **Project period:** 2019-05-01 → 2023-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9913545

## Citation

> US National Institutes of Health, RePORTER application 9913545, Changes in corneal mechanics due to glycosaminoglycan depletion and corneal cross-linking therapy (5R21EY030264-02). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9913545. Licensed CC0.

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