Transscleral Selective Laser Trabeculoplasty Project

Inclusion Criteria: * Age 18 years or older with OAG or OHT who are clinical candidates for routine SLT. * Mild to moderate OAG (defined as a mean deviation on the Humhprey Field Analyzer \[HFA\] \> -12.0 dB), resulting from primary open-angle glaucoma (POAG), or pseudoexfoliative glaucoma * OHT with open angles warranting IOP-lowering treatment * IOP ≥ 22mmHg or ≤ 35mmHg (after washout of any IOP-lowering medications) * Gonioscopically visible scleral spur for 360 degrees without indentation * Ability to visualize the peri-limbal sclera for 360 degrees (using a manual elevation of the lid) * Willing and able to participate in the 60 days +/-5 days study, to comply with the study procedures and to adhere to the follow-up schedule. * Participant capable of giving informed consent Exclusion Criteria: * Contraindications to conventional SLT (e.g. corneal abnormalities etc.) * Angle Closure Glaucoma * Congenital or developmental glaucoma * Secondary glaucoma included pigmentary glaucoma * Inability to conduct a reliable visual field (defined as fixation losses, false positives or false negatives greater than 33%) * Presence of any peripheral anterior synechiae (PAS) in the study eye * Any of the following visual field findings using the Humphrey visual field analyzer: * A HFA MD of worse than -12dB * Greater than or equal to 75% of points depressed below the 5% level and greater than or equal to 50% of points depressed below the 1% level on the PD plot * At least 50% of points (i.e., 2 or more) within the central 5 degrees with a sensitivity ≤0dB on the decibel plot * Points within the central 5 degrees of fixation with a sensitivity \<15 dB in both hemifields on the decibel plot * A visual field MD of worse than -12dB in the fellow eye * Cup: Disc Ratio more than 0.8 * More than two hypotensive medications required (combination drops are considered 2 medications) * Prior incisional or laser glaucoma surgery (including previous SLT) in the study eye * Prior corneal refractive surgery * Complicated cataract surgery ≤ 6 months prior to enrollment * Presence of visually significant cataract in the opinion of the investigator * Clinically significant disease in either eye as determined by the Investigator * Clinically significant amblyopia in either eye * Dense pigmentation or hemorrhage in the peri-limbal conjunctiva or anterior sclera, Pigmented Pinguecula and Pterigium * Women who are pregnant or may become pregnant during the course of the study * In the opinion of the investigator the participant might require other ocular surgery within the 12-months, unless for further reduction of their IOP. * Concurrent treatment with topical, nasal, inhaled or systemic steroids. * Uncontrolled systemic disease that could impact the ability of the participant to attend follow up visits as per the discretion of the investigator * Participation in another clinical study * Protected or vulnerable subjects (including but not limited to people with impaired intellectual functioning or mental illness, prisoners, terminally ill subjects, immunocompromised…) * People not able to read and understand the informed consent * People not able to read and understand English language