Measuring corneal stiffness in glaucoma with Brillouin microscopy

Development of Robust Corneal Biomechanical Biomarkers for Glaucoma Using Brillouin Microscopy

We will use Brillouin microscopy to see if corneal stiffness differs between adults with normal-tension glaucoma, high-tension glaucoma, and people without glaucoma, and whether stiffness changes after common IOP-lowering eye drops.

Quick facts

• Study type: Observational
• Enrollment: 60 (estimated)
• Ages: 18 Years and up
• Sex: All
• Sponsor: University of Maryland, Baltimore (Academic / other)
• Locations: 1 site (Baltimore, Maryland)
• Trial ID: NCT06993597 on ClinicalTrials.gov

What this trial studies

This observational pilot enrolls adults with primary open-angle glaucoma (high- and normal-tension) and age-matched healthy controls for cross-sectional and longitudinal imaging. Participants undergo non-contact Brillouin microscopy to measure corneal biomechanical properties, with baseline comparisons across the three groups. Glaucoma participants who start prostaglandin analogs or topical beta blockers will have repeat imaging to detect treatment-related changes over time. The study aims to determine whether Brillouin-derived stiffness measures could serve as biomarkers for glaucoma susceptibility or progression and to evaluate the technique's feasibility in clinical care.

Who should consider this trial

Good fit: Adults (≥18) with primary open-angle glaucoma—either high-tension (IOP ≥22 mmHg on three visits) or normal-tension (IOP ≤21 mmHg on three visits)—or age-matched controls with normal optic nerves and visual fields, good visual acuity, refractive error within study limits, open angles, and no prior topical glaucoma medication use are ideal candidates.

Not a fit: Patients with corneal abnormalities, prior ocular surgery or laser, retinal disease affecting RNFL, diabetes, uveitis, prolonged steroid use, neurodegenerative or systemic disorders, unreliable visual fields, or contraindications to beta blockers are excluded and unlikely to benefit from participation.

Why it matters

Potential benefit: If successful, Brillouin-derived corneal stiffness measures could help identify patients at higher risk of glaucoma progression and guide more personalized treatment decisions.

How similar studies have performed: Brillouin microscopy is a relatively new, non-contact technique with limited clinical data; small prior studies suggest a link between corneal biomechanics and glaucoma risk, so this approach is novel but builds on early evidence.

Eligibility criteria

Inclusion Criteria:

\- Age 18 years or older

Diagnosis of primary open angle glaucoma (POAG) or no history of glaucoma (for controls)

Open angle on gonioscopy (Shaffer grade 3 or 4)

Best-corrected visual acuity of 20/25 or better

Refractive error between +3.00 and -5.00 diopters

No prior use of topical glaucoma medications

Diagnosis of:

High Tension Glaucoma (IOP ≥ 22 mmHg on 3 visits)

Normal Tension Glaucoma (IOP ≤ 21 mmHg on 3 visits)

OR age-matched control with normal optic nerve and visual fields

Exclusion Criteria:

Corneal abnormalities or conditions interfering with Brillouin or applanation tonometry

Retinal diseases affecting RNFL (e.g., macular traction)

History of ocular surgery or laser

Diagnosis of diabetes

History of uveitis

History of prolonged steroid use

Neurodegenerative or systemic diseases (e.g., multiple sclerosis, Alzheimer's, Parkinson's, schizophrenia)

Unreliable visual fields

Contraindications to beta blockers (e.g., bradycardia, severe pulmonary disease)

Moderate to severe glaucoma (per Hodapp-Anderson-Parrish criteria)

History of contact lens use

Low blood pressure

Where this trial is running

Baltimore, Maryland

• University of Maryland School of Medicine — Baltimore, Maryland, United States (Recruiting)

Study contacts

• Principal investigator: Osamah Saeedi, MD — University of Maryland, Baltimore
• Study coordinator: Osamah Saeedi, MD

Conditions Glaucoma; glaucoma; cornea; biomechanics