Glaucoma Laser Assessment of Stability and Sustainability

The GLASS Study (Glaucoma Laser Assessment of Sequential Sessions) is a prospective, interventional, paired-eye, single-site, investigator-initiated clinical trial designed to evaluate the safety and effectiveness of repeated applications of Direct Selective Laser Trabeculoplasty (DSLT) in treatment-naive patients with ocular hypertension (OHT), glaucoma suspect, or mild to moderate primary open-angle glaucoma (POAG).

DSLT is a non-contact, automated laser procedure that delivers 120 laser pulses evenly around the limbus to stimulate aqueous outflow by targeting the trabecular meshwork. The procedure is performed with the patient in an upright seated position using the Voyager DSLT device (Alcon). Unlike conventional SLT, this method does not require gonioscopy, coupling gel, or a contact lens.

All enrolled subjects must be treatment-naive, meaning they have not previously been on any ocular hypotensive medications. Eligible subjects will first complete a screening visit to verify inclusion and exclusion criteria. If criteria are met, they will be enrolled and proceed to the Baseline visit, where both eyes will undergo DSLT.

At the 3-month visit, one randomly selected eye (the "dual-treatment eye") will undergo a second DSLT session. The fellow eye (the "single-treatment eye") will receive no further laser treatment and serve as a control. Subjects will continue follow-up visits at 4 months (1 month after the second treatment), 6 months, 9 months, and 12 months from the baseline treatment.

Each study visit will include assessments such as best-corrected visual acuity (BCVA), intraocular pressure (IOP) via Goldmann applanation tonometry, slit-lamp examination, adverse event monitoring, ocular medication review (if applicable), and specular microscopy to assess corneal endothelial cell density. The primary endpoint is the difference in mean IOP between the dual-treatment and single-treatment eyes at 12 months.

Secondary endpoints include change in IOP from baseline at each follow-up timepoint, time to re-initiation of ocular hypotensive medications, and any difference in safety or complication rates between the two eyes.

The hypothesis is that a second treatment at the 3-month mark will provide enhanced and more durable IOP reduction, possibly reducing or delaying the need for medication. While DSLT has been studied previously in single-treatment applications, this is the first prospective trial evaluating repeat bilateral DSLT in a paired-eye design using one eye as its own internal control.

All procedures will be conducted at Twin Cities Eye Consultants in Minnesota. The study is sponsored and monitored internally by Twin Cities Eye Consultants' Research Committee, who will oversee compliance, data integrity, and protocol adherence.

Inclusion criteria

• Male and female patients aged 40 years or older
• A bilateral diagnosis of ocular hypertension, glaucoma suspect, or mild primary open angle glaucoma as defined by AAO PPP
• Treatment naïve with an unmedicated IOP between 21-35 mmHg, inclusive, and within +/- 3mmHg of each eye to be eligible
• BCVA of 20/50 or better
• The subject is able to read and understand the requirements of the study and provide written informed consent.
• The subject is willing to follow study instructions, agrees to comply with all study procedures and attend all scheduled follow-up exams for 12 months after the initial treatment.

Exclusion criteria

• Unable to view scleral spur inferiorly with gonioscopy.
• Congenital or developmental glaucoma, angle closure glaucoma, secondary glaucoma (e.g. exfoliative, pigmentary, etc.) pigmentary, neovascular glaucoma, closed angle glaucoma, or uveitic glaucoma.
• Use of oral or ocular hypotensive medication for glaucoma.
• Prior history of ocular surgery except for cataract surgery (must be ≥ 2 years prior)
• Clinically significant ocular pathology, other than cataract and glaucoma, including but not limited to neovascular age-related macular degeneration, advanced dry macular degeneration, and proliferative diabetic retinopathy, etc.
• Clinically significant ocular inflammation or infection within 6 months prior to screening.
• Previous corneal transplant or clinically significant corneal dystrophy, e.g., Fuch's dystrophy (≥12 confluent guttae)
• Unclear ocular media prevent visualization of the fundus or anterior chamber angle.
• Uncontrolled systemic disease that in the opinion of the Investigator would put the subject's health at risk and/or prevent the subject from completing all study visits.
• Current participation in another investigational drug or device clinical trial (which includes the fellow eye) within the past 30 calendar days.
• Pregnant or nursing women; or women of childbearing age not using medically acceptable contraceptives.

Accepted prior ocular procedures:

• Cataract surgery (if ≥ 2 years or screening)
• YAG capsulotomy (if ≥ 60 days of screening)