Insights into intraocular pressure spikes following gonioscopy-assisted transluminal trabeculotomy (GATT): timing, predictors and clinical outcomes.

Purpose: To evaluate the frequency, timing, and characteristics of intraocular pressure (IOP) spikes following standalone Gonioscopy-Assisted Transluminal Trabeculotomy (GATT), and to assess their predictors and management strategies.

Study design: A retrospective observational study.

Methods: A total of 210 eyes that underwent 360° GATT between September 2021 and January 2024 at our tertiary eye hospital were included. Demographics, best-corrected visual-acuity (BCVA), IOP, antiglaucoma medications, complications and interventions were recorded. IOP spikes were defined as >30 mmHg or >10 mmHg above baseline within two months postoperatively and classified as hyperacute (0-3 days), acute (4-9 days), or subacute (10-60 days). Surgical success was defined as IOP: 5-21 mmHg with ≥20% reduction from baseline. Primary outcomes included spike characteristics, associated factors, and success rates.

Results: Seventy-one eyes (33.8%) developed IOP spikes, with a mean IOP of 33.9±6.5 mmHg and duration of 2.0 ± 2.6 days. Hyperacute spikes had more fibrinoid reaction (p=0.026) and higher total success (p=0.049); acute spikes had higher maximal preoperative IOP and longer hyphema duration (p=0.02, p=0.006, respectively); and subacute spikes had prolonged topical corticosteroid use, longer axial length, and prior vitrectomy (p=0.003, p=0.04, p=0.004, respectively). Total surgical success was 91.9%, with higher rates in the non-spike group (99.3% vs. 77.5%, p<0.001). Fibrinoid reaction, prolonged topical corticosteroid use, and prior vitrectomy were associated with postoperative IOP spikes.

Conclusion: Postoperative IOP spikes are significantly correlated with surgical failure following GATT. Their timing might reflect differences in underlying mechanisms. Prompt management of complications associated with IOP spikes is essential to reduce failure.