Navigating the Angles: A Retrospective Analysis of One-year Outcomes of Gonioscopy-assisted Transluminal Trabeculotomy in Primary Open-angle Glaucoma.

This study aimed to evaluate postoperative angle changes following gonioscopy-assisted transluminal trabeculotomy (GATT) in patients with primary open-angle glaucoma (POAG) over 1 year of follow-up. We conducted a retrospective analysis of 60 eyes from 41 POAG patients who underwent GATT, assessing intraocular pressure (IOP), number of ocular hypotensive medications, and gonioscopic findings preoperatively and at 3, 6, and 12 months postoperatively using the Spaeth classification. Postoperative IOP and medication use were significantly reduced throughout follow-up. Gonioscopic examination revealed forward movement of the iris root insertion in all quadrants, most notably inferiorly, with angle width narrowing up to 10°, primarily in the nasal quadrant. Overall pigment angle decreased initially, then gradually increased, with the nasal quadrant showing the highest pigment levels; the pigment pattern changed from diffuse preoperatively to stacked postoperatively. Peripheral anterior synechia (PAS) developed in 39 eyes (65%) and stabilized by 3 months, with the nasal quadrant most affected and showing a gradually increasing extent of involvement. Regarding the trabeculotomy cleft, 28 eyes (46.7%) maintained a widely patent opening, 29 (48.3%) showed a narrow opening, and 3 (5%) were completely closed. Angle rebleeding sites varied among patients, occurring most frequently in the nasal quadrant. In conclusion, GATT significantly reduced IOP and medication use over 12 months, with characteristic angle changes including forward iris insertion, narrowing angle width, altered pigment distribution with accumulation, predominant PAS formation in the nasal quadrant, and variable rebleeding sites.