This pilot study evaluates the biomechanical properties of the cornea in glaucoma patients using Brillouin microscopy, a non-contact imaging technique. The study aims to compare corneal stiffness between patients with normal-tension glaucoma, high-tension glaucoma, and healthy controls, and to assess changes in corneal biomechanics following intraocular pressure (IOP)-lowering treatment. The goal is to determine whether Brillouin-derived biomechanical measurements can serve as biomarkers for glaucoma risk and progression.

This study explores the biomechanical properties of the cornea in patients with glaucoma using a novel, non-contact imaging technique called Brillouin microscopy. The technology allows in vivo assessment of tissue stiffness without physical perturbation, potentially offering new insights into glaucoma risk and response to therapy.

The study includes two parts: a cross-sectional comparison between patients with normal- and high-tension glaucoma and healthy controls, and a longitudinal analysis of biomechanical changes following IOP-lowering treatment with either prostaglandin analogs or beta blockers.

The goal is to determine whether corneal biomechanics can serve as a biomarker for glaucoma susceptibility and progression, and to evaluate the feasibility of integrating Brillouin imaging into clinical glaucoma care.

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

The study population includes adults aged 18 years and older with newly diagnosed, treatment-naïve primary open angle glaucoma (POAG), including both normal tension glaucoma (NTG) and high tension glaucoma (HTG), as well as age-matched healthy control subjects. Subjects must meet strict ophthalmic inclusion criteria and will be recruited from the University of Maryland Department of Ophthalmology and Visual Sciences and affiliated clinics. Exclusion criteria include significant ocular comorbidities, prior ocular surgery, systemic diseases that affect the eye, or prior glaucoma therapy.

Individual participant data will not be shared. Summary-level results will be published and made publicly available per NIH policy.