This is a prospective, single-center, single-arm, observational study designed to evaluate the change in diurnal intraocular pressure (IOP) fluctuation following Direct Selective Laser Trabeculoplasty (DSLT) in patients with primary open-angle glaucoma (POAG) who are on 1-3 IOP lowering medications. The study will be conducted at one site and will involve three key visits: a screening visit, a baseline/treatment visit, and a 6-month follow-up visit. During the screening visit, patients will undergo a comprehensive ophthalmic examination, and eligibility will be confirmed. The eye with the higher IOP will be selected if both eyes are eligible. At the baseline visit, diurnal IOP will be recorded at three time points (9am, 12pm, and 4pm) before DSLT is performed. The primary endpoint is the change in diurnal IOP fluctuation 6 months post-treatment. Secondary endpoints include changes in mean diurnal IOP and the proportion of eyes achieving a reduction in IOP fluctuations of ≥1 mmHg. Exploratory endpoints focus on demographic variables associated with IOP fluctuation changes.

Inclusion Criteria:

Visit 1 (Screening)

• Subject status as follows:

  1. Male or female, 18 years of age or older.
  2. Able and willing to attend scheduled follow-up exams for 6 months post-operatively.
  3. Able and willing to provide written informed consent on the IRB-approved Informed Consent Form.

• Diagnosis of OAG (i.e., primary, pseudoexfoliation, or pigmentary glaucoma) of any severity or OHT in the study eye (i.e., eye to undergo surgery).

• IOP-lowering medication regimen in the study eye as follows:

  a. Zero to three topical IOP-lowering medication classes at the time of Visit 1 (Screening) exam (Note: fixed combination medications [e.g., Cosopt®, Combigan®, Rocklatan®, Simbrinza®] count as two medications).

• Angle anatomy in the study eye defined as follows:

  1. Trabecular meshwork visible on gonioscopy defined by Shaffer grade ≥ 3.
  2. Normal anatomy as determined by gonioscopy.
  3. Absence of peripheral anterior synechia (PAS), rubeosis or other angle abnormalities that could impair proper DSLT treatment.

Visit 2 (Baseline/Treatment)

• Medicated mean diurnal IOP (based on 8AM, 10AM and 4PM assessments) of ≥ 16 mmHg and less than or equal to 30 mmHg.
• Able and willing to attend scheduled follow-up exams for 6 months post-operatively.
• Successful DSLT treatment.

Exclusion Criteria:

Visit 1 (Screening)

• Status in the study eye as follows:

  1. Traumatic, malignant, uveitic, neovascular, or angle-closure glaucoma; or glaucoma associated with vascular disorders.
  2. Functionally significant visual field loss, including severe nerve fiber bundle defects.
  3. Visual field (mean deviation) worse than -20 dB using 24-2 SITA Standard or equivalent.
  4. Prior incisional glaucoma surgery or ALT, or prior MIGS surgery.
  5. History of iridotomy, SLT, or MicroPulse Laser Trabeculoplasty (MLT) within the past 2 years.

• Unable to provide an adequate and interpretable visual field examination result (i.e., fixation losses, false positives and false negatives must all be less than 33%) in the study eye.

• Vertical C/D ratio > 0.8 in the study eye.

• Presence of retrobulbar tumor, thyroid eye disease, Sturge-Weber Syndrome or any other type of condition that may cause elevated episcleral venous pressure.

• Corneal status in the study eye as follows:

  1. Any active inflammation or edema (e.g., keratitis, keratoconjunctivitis, keratouveitis).
  2. Corneal endothelial dystrophy (e.g., bullous keratopathy, Fuch's dystrophy, guttata).
  3. Prior corneal transplantation, or endothelial cell transplants (e.g., Descemet's Stripping Automated Endothelial Keratoplasty [DSAEK]).
  4. Significant scarring or irregularities (including scars from prior corneal surgery such as PKP, RK, etc.) that may interfere with reliability of applanation IOP measurement anticipated corneal surgery of any type (including LASIK, LASEK, PRK, etc.).

• Lens status in the study eye:

  1. Visually significant cataract expected to require cataract surgery within the next 6 months.
  2. Cataract surgery within 24 months prior to Visit 1 (Screening).
  3. Anterior chamber intraocular lens (IOL) or implantable contact lens.
  4. Congenital or traumatic cataract (except Mittendorf dots).

• Choroidal detachment, effusion, choroiditis, neovascularization, or any active choroidopathy.

• Retinal or optic nerve disorders in either eye, either degenerative or evolutive, that are not associated with the existing glaucoma condition, including proliferative diabetic retinopathy (mild background diabetic retinopathy permissible), central retinal artery occlusion, central retinal vein occlusion, wet age-related macular degeneration, advanced dry age-related macular degeneration, (e.g., presence of numerous large drusen associated with disturbance to or elevation of the retinal pigment epithelium), significant retinal pigment epithelial changes or optic atrophy.

• Other ocular status in the study eye as follows:

  1. Clinically significant sequelae from trauma (e.g., chemical burns, blunt trauma).
  2. History of chronic ocular inflammatory disease or presence of active ocular inflammation (e.g., uveitis, iritis, iridocyclitis, retinitis, ocular herpes).
  3. Prior administration of a glaucoma stent (e.g., iStent, Hydrus Microstent).
  4. Prior administration of an intracameral implant or drug product (e.g., Travoprost Intraocular Implant, Durysta [bimatoprost intracameral implant], Dexycu [dexamethasone intraocular suspension]).
  5. Any pathology for which, in the investigator's judgment, the following would be either at risk or contraindicated:

  i. Implantation of iStent infinite. ii. Implantation of a Travoprost Intraocular Implant. iii. Compliance to elements of the study protocol (e.g., ophthalmic examinations, follow-up visits).

• Fellow eye status as follows:

  1. Best spectacle corrected visual acuity of worse than 20/200.
  2. Fellow eye actively enrolled in this trial or any other clinical trial.

• Subject status as follows:

  1. Breast-feeding, pregnant or planning to become pregnant during the course of the study.
  2. Uncontrolled systemic disease (e.g., diabetes, hypertension) that could compromise participation in the study.
  3. Immunodeficiency conditions.
  4. Use within 30 calendar days of Visit 1 (Screening) or anticipated use during the study of any ophthalmic steroid, or any oral, parenteral, injected, or orally inhaled steroid medication that may cause an increase in IOP. Note: Nasally inhaled steroids are acceptable, as are topical dermal steroids provided they are not applied to the face.
  5. Current participation in any study, or participation within 30 days of Visit 1 (Screening).
  6. Current (within 30 days) or anticipated use of systemic acetazolamide or methazolamide.
  7. Change in an existing chronic systemic therapy that could substantially affect IOP or the study outcomes within 30 days prior to Visit 1 (Screening), or anticipated change during the study.
  8. Any ocular disease or condition that, in the opinion of the Investigator, may put the subject at significant risk, may confound the study results, or may interfere significantly with the subject's participation in the study.
  9. CCT>620.

Adults aged 18 years or older diagnosed with OAG or OHT, eligible for DSLT treatment.